VS2.5 Transmitter. Troubleshooting Manual. Document: VS2.5-TROUBLESHOOT. Issue:

Transcription

1 VS.5 Transmitter Troubleshooting Manual Document: VS.5-TROUBLESHOOT Issue: Status: Preliminary

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3 Nautel Limited 0089 Peggy s Cove Road Hackett s Cove, NS Canada B3Z 3J4 Phone: or Toll Free: NAUTEL (668835) (Canada & USA only) Fax: Nautel Inc. 0 Target Industrial Circle Bangor, Maine USA 0440 Phone: Fax: Customer Service (4 hour support) (Canada & USA only) (International) support@nautel.com Web: The comparisons and other information provided in this document have been prepared in good faith based on publicly available information. The reader is encouraged to consult the respective manufacturer's most recent published data for verification. Copyright 00 NAUTEL. All rights reserved.

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5 Table of contents Contents Release control record About this manual About safety Safety precautions ix xi xv xvii Responding to alarms - Corrective maintenance - Electrostatic protection -3 Identifying an alarm -4 Troubleshooting tips -5 Operating with defective PAs or cooling fans -6 Replacing a suspect PWB, power supply or fan -7 PA PWB replacement -9 Pre-amp/IPA PWB replacement -3 Power Supply Module Replacement V Power Supply Replacement -35 Cooling fan replacement - fans 3 (B3) through 7 (B7) -36 Cooling fan replacement - fans (B) and (B) -38 Exciter/Control PWB Replacement -40 PS Distribution PWB Replacement -43 Combiner Interface PWB Replacement -45 Detailed Circuit Descriptions - Exciter/control PWB (NAPE83A) - PS distribution PWB (NAPS43) - Page v

6 Table of contents Pre-amp/IPA PWB (NAPA8A) -3 Power amplifier PWB (NAPA3) -4 Parts Lists 3- Parts information 3- Family tree 3- How to locate information about a specific part 3- Column content 3- OEM code to manufacturer s cross-reference 3-3 Common abbreviations/acronyms 3-4 Wiring/connector lists 4- Wiring lists provided 4- Wiring lists not provided 4- Connector mating information 4- Wire colours 4- Printed wiring board patterns 4- Reading Electrical Schematics 5- Component values 5- Graphic symbols 5- Logic symbols 5- Reference designations 5- Unique symbols 5- Identifying schematic diagrams 5- Structure of schematics 5- Locating schematic diagram(s) for a functional block 5-3 Locating a part or assembly on a schematic 5-3 Mechanical Drawings 6- Identifying mechanical drawings 6- Content of mechanical drawings 6- Page vi Issue

7 Table of contents Locating a part or assembly on a mechanical drawing 6- List of terms 7- Issue Page vii

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9 Release control record Issue Date Reason Initial release of manual Pre-amp/IPA PWB A5 changed to NAPA8A. Affects replacement procedure in section, parts list in section 3, wiring list in section 4 Issue Page ix

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11 About this manual This manual provides troubleshooting information for the VS.5 transmitter. It is intended for use by field technicians. This manual allows the troubleshooting technician to diagnose a fault to the system level, using alarm response procedures, parts lists, wiring lists, and electrical schematics. Electrical schematics and mechanical drawings are included at the end of the manual. Performing procedures When using procedures in this manual, perform each step in sequence. If you are asked to see another section of this manual, or another document, refer to that section or document for additional information, then continue the procedure. If you are asked to go to another step within the procedure, jump directly to that step without performing the intervening steps. If you are asked to go to another section or document, stop the procedure and perform the tasks described in the other section or document. If you are asked to check a voltage, use a digital voltmeter and test the voltage relative to ground (unless otherwise instructed). If you are asked to check a signal, use an oscilloscope and test the signal relative to ground (unless otherwise instructed). Technical support Nautel offers technical support to customers over the Internet and by telephone. Nautel s customer support team will answer your questions and work with you to identify and resolve problems. For 4-hour technical support, call toll free at (in USA and Canada only) or call (international) or find us on the Internet at For parts and tools information, see Parts and tools on page 9- of the VS.5 Pre-Installation Manual. Issue Page xi

12 For extended warranty information, see Pre-installation assistance on page 0- of the VS.5 Pre-Installation Manual. VS.5 transmitter manuals The VS.5 documentation suite includes the following documents: VS.5 Pre-installation Manual, VS.5-PREINST. Provides instructions and reference information needed when planning and preparing for the installation of a VS.5 transmitter. Nautel Site Protection Manual. Provides detailed information about protecting your site from lightning-related hazards. VS.5 Installation Manual, VS.5-INST. Provides instructions and reference information needed when installing a VS.5 transmitter. VS.5 Operating and Maintenance Manual, VS.5-OPS-MAINT. Provides instructions for operating, maintaining and troubleshooting a VS.5 transmitter. It also provides reference information needed when performing diagnostic procedures. VS.5 Troubleshooting Manual, VS.5-TROUBLE. Provides detailed technical information about the VS.5 transmitter, including electrical schematics and mechanical drawings. Nautel website / Online resources The Nautel website provides useful resources to keep you up to date on your VS.5. Nautel User Group (NUG) The website includes a special section that customers can log into in order to access the Nautel customer newsletter, product manuals, frequently asked questions (FAQ), information sheets, and information about field upgrades. Documentation: online and printed The website s NUG section provides online access to all the documentation for your VS.5. Documentation is provided in Acrobat (PDF) format. You can use the documentation online or print the sections that you need. When using online documents: Page xii Issue

13 Click on blue text (hyperlinks) to jump to a related section, or to get additional information (e.g., view a term s definition). To search a document to find keywords, use Find in Acrobat Reader s Edit menu. To quickly find a specific section, click the section in the PDF file s Bookmarks list. When using printed documents: To find a specific term, go to the List of Terms section near the end of the manual. Issue Page xiii

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15 About safety All Nautel transmitters are designed to meet the requirements of EN605, Safety Requirements for Radio Transmitters. The philosophy of EN605 is that the removal of any cover or panel that can only be opened using a tool is a maintenance activity, and that any person performing a maintenance activity is expected to be trained for that activity. Under EN605, it is assumed that trained personnel will be knowledgeable and will take precautions such as removing all power to the transmitter before accessing its components. Electrical hazards To remove power from the transmitter, switch off and lock out the ac power. DANGER - HIGH VOLTAGE Indicates dangerous voltage (in excess of 7 volts), capable of causing a fatal electrical shock, are present on or near parts bearing this label. WARNING: It is not enough to switch off RF power. The power line is still connected. Disconnect and lock out the upstream supply before servicing. After turning off the ac power, always perform a measurement to confirm that the power is off before touching anything within the transmitter. If the wrong breaker was opened, the equipment will be live. WARNING: Do not use an ordinary multimeter to check for voltage, since it may have been left inadvertently on the AMP (A) range, triggering a short and an arc blast that could result in severe burns and even death. Use only a non-contact voltage probe or a safety voltmeter (available from vendors such as Fluke, Ideal, and Teagam). Use a proper lockout procedure to ensure that another worker cannot accidentally reapply power while you are performing maintenance on any part of the transmitter or site. Issue Page xv

16 Lightning hazards Before opening the transmitter and touching internal parts, remove and solidly ground the antenna connection. WARNING: It is not enough to ground the antenna terminal with the antenna still connected. Even a small impedance in the ground strap will result in lethal voltages during a lightning strike. RF hazards A serious RF hazard and very high voltages exist in the vicinity of the antenna and its networks during normal operations. Toxic hazards Some devices used in this equipment contain beryllium oxide ceramic, which is non-hazardous during normal device operation and under normal device failure conditions. These devices are specifically identified with (BeO) in the Description column of the Troubleshooting Manual s parts list(s). Do not cut, crush or grind devices because the resulting dust may be hazardous if inhaled. Unserviceable devices should be disposed of as harmful waste. Physical hazards DANGER - MOVING BLADES Fan blades can cause injury. Lock out power before removing safety features. Other hazards Ensure that appropriate fire alarms and fire extinguishers are available. Extinguishers must be suitable for use on electrical fires. Many other site safety risks exist. It is beyond the scope of this manual to identify all the risks and procedures. Page xvi Issue

17 Safety precautions This section provides very important information about protecting the safety of personnel and equipment: Personal safety - see page xvii Site safety - see page xviii Equipment safety - see page xx Personal safety Training The training of any personnel who will have physical access to the site or the transmitter is very important. Personnel must be familiar with the transmitter, so that they can avoid physical danger, and be aware of hazards to themselves and the equipment. Nautel offers a number of training courses covering the basic fundamentals of RF systems and transmitters, and the operation and maintenance of the transmitter. For more information about available courses and schedules, go to the Nautel website at or ask your Nautel sales representative. Site orientation When you give personnel access to the transmitter site (e.g., hiring new personnel, or giving access keys to personnel), perform a site orientation to ensure that they are familiar with the site, on-site procedures, and on-site hazards. Cover the following topics: Securing the site (locking doors and fences) to prevent unauthorized access How and when to call for technical support or emergency assistance Areas of the site and pieces of equipment that are off limits Issue Page xvii

18 Voltage awareness Ensure that all personnel that are able to access areas with high voltage circuits or high field strengths are aware of the hazards associated with high voltage. Cover the following topics: High voltage or high field strength areas where caution is required Physical risks of electric shock Risks for personnel with pacemakers or other medical implants Induced voltages in high field strength areas On-site risks during thunderstorms and lightning strikes Operation of safety interlocks (if installed) First aid Nautel does not offer first aid training, since the hazards associated with high voltage and RF energy are not specific to the transmitter. However, the customer should provide first aid training to all personnel who have access to the transmitter site. First aid training should include CPR, care of burns, artificial respiration, and defibrillation if specific equipment is available on-site. Site safety Controlling access Transmitters and antennas generate and carry dangerous voltages that can be harmful or fatal. It is very important that you control access to the site and its equipment. To secure your transmitter site, use: Locking steel or security doors to prevent casual access A perimeter fence to keep trespassers away from the antenna system and feedline No Trespassing signs An alarm system Page xviii Issue

19 Marking hazards Place warning signs close to any hazardous areas or systems (e.g., the feedline or the antenna system). Make the signs large enough that they cannot be missed. Provide signage in all languages used in the region. These signs are intended not only for authorized personnel, but also for emergency responders or accidental trespassers. Qualifying site personnel Make sure that personnel who have access to the site are qualified to work around electronics and high voltage systems. Ac power protection You should take steps to protect equipment from surges (over-voltage spikes) on the ac power lines. Surges may occur during thunderstorms, or because of malfunctions in the electrical distribution grid. Surge suppressors and ac power conditioners can prevent serious damage to your on-site equipment, including the transmitter. RF protection Transmitters and their antenna systems create intense radio frequency fields at the transmitter site, particularly near the feedline, antenna and tower. At some sites, these fields may cause biological effects, including the heating of body tissues. Intense fields can also create dangerous high voltages on ungrounded, conductive surfaces and objects. At certain points where high voltage conductors come close to grounded conductors (e.g., at feedline junctions or on the tower), dangerous electrical arcing or flashovers can occur. It is very important that you take the following steps to prevent damage to equipment or personnel due to RF fields: Use safety interlocks to de-energize transmitters if personnel open doors or panels accessing high field areas Place warning signs in any locations where high fields can occur Train personnel about the short-term and long-term hazards of RF radiation Physically block access to the area around the antenna system, feedline and tower Ground all exposed conductive surfaces or objects in high field areas The RF connection to the transmitter output can be a serious safety hazard. Connect a 50 Ω test load during installation and commissioning. It is recommended that a switch be used to automatically connect the transmitter to the antenna system without human contact with the transmitting conductors. Issue Page xix

20 Safety interlocks The transmitter contains an electrical interlock, which is an external circuit that turns off the RF output if any of its switches are opened. Equipment safety Electrostatic protection The transmitter s systems are very rugged and resistant to damage. However, it is possible for damage to occur because of high voltage electrostatic discharges during servicing. Train all service personnel to ground themselves to bleed off any static charge before opening the transmitter or touching any exposed components. Provide a grounding wand or known ground (e.g., a grounded metal table) that personnel can use to discharge themselves. Surge protection Surge protection is recommended for your entire site. However, even if you do not use a surge protector on the service entrance to the site, you should install a surge protector in the transmitter s ac power feed to prevent over-voltage from entering the transmitter. Lightning protection The transmitter is designed to resist lightning strike damage. However, intense or repeated strikes could damage the transmitter. We recommend that you install lightning suppression on the antenna, tower and feedline to reduce the effect of lightning strikes on the transmitter itself (and to protect the rest of your site equipment and your personnel). For detailed information about lightning protection, see the Nautel Site Preparation Manual, available from your Nautel sales agent, or online from the Nautel website. Physical protection Consider physical hazards to equipment at your site, including the transmitter. Ensure that equipment is protected from weather (e.g., rain or flooding), even during extreme weather events. Place equipment so that it is not in the path of swinging doors or high-traffic areas. Do not allow wheeled items like office chairs or tables with wheels in the transmitter room, as these may damage equipment if accidentally pushed or knocked over. Do not place the transmitter under water pipes, drains, or sprinklers. Keep any equipment that generates heat, like the transmitter, away from flammable materials like ceiling panels, cubicle dividers, and curtains. Page xx Issue

21 Responding to alarms Section : Responding to alarms This section provides instructions you need when performing troubleshooting on the VS.5 transmitter. This section includes the following topics: Corrective maintenance Electrostatic protection - see page -3 Identifying an alarm - see page -4 Troubleshooting tips - see page -5 AUI lockup - see page -5 Operating with defective PAs or cooling fans - see page -6 Replacing a suspect PWB, power supply or fan - see page -7 If none of the procedures and alarms described in this section address your problem, contact Nautel for assistance. See Technical support on page viii. Corrective maintenance Corrective maintenance procedures consist of identifying and correcting defects or deficiencies that arise during transmitter operation. Local and/or remote alarm signals are generated when a malfunction occurs. If an alarm condition is caused by a malfunction in the RF power stage, the transmitter may maintain operation at a reduced RF output level. The nature of the fault and station policy will dictate whether an immediate maintenance response is necessary. Fault analysis and rectification may be conducted from three different levels, with a different technical competence level required for each: on-air troubleshooting, remote or local, and off-air troubleshooting. CAUTION: The transmitter contains many solid state devices that may be damaged if subjected to excessive heat or high voltage transients. Every effort must be taken to ensure that circuits are not overdriven or disconnected from their loads while turned on. On-air troubleshooting On-air troubleshooting can be performed from a remote location, or locally at the transmitter site. Issue Page -

22 Responding to alarms Remote troubleshooting Remote on-air troubleshooting consists of monitoring the transmitter's radiated signal using an on-air monitor or via a LAN connection, and observing the status of each remote fault alarm indicator. Information obtained from these sources should enable an operator to decide whether an alarm response may be deferred to a more convenient time, an immediate corrective action must be taken, or if a standby transmitter must be enabled (if one is available). It is recommended that the significance of remote indications, and the appropriate responses, be incorporated into a station's standard operating procedures. Refer to Identifying an alarm on page -4 to determine the remedial action required for a given fault. Local troubleshooting Local on-air troubleshooting consists of monitoring the transmitter's integral meters and fault alarm indicators. Analysis of this data will normally identify the type of fault, and in most cases will determine what corrective action must be taken. Refer to Identifying an alarm on page -4 to determine the remedial action required for a given fault. The power amplifier stage contains an integral modular reserve (IMR) feature. This feature permits the transmitter to operate at a reduced RF output level when a malfunction occurs in one of its power modules. Station operating procedures will dictate whether a reduced RF output level is acceptable. When a reduced RF output level can be tolerated, replacement of the defective RF components may be deferred to a convenient time. Off-air troubleshooting Off-air troubleshooting must be performed when routine on-air calibration adjustments will not restore operation. It is recommended that the transmitter s output be connected to a precision 50 Ω resistive dummy load (rated for at least the maximum transmitter power rating of 500 W) before starting off-air troubleshooting procedures. If an appropriate dummy load is not available, troubleshooting for a majority of faults can be performed with the RF power stage turned off. The transmitter may remain connected to its antenna system for these procedures. CAUTION: Reduce the RF output level to a minimal value when troubleshooting faults in the transmitter. This is particularly important when the transmitter s cover is removed - where possible overheating could occur - or when the transmitter is connected to the antenna system. Page - Issue

23 Responding to alarms Electrostatic protection The transmitter's assemblies contain semiconductor devices that are susceptible to damage from electrostatic discharge. The following precautions must be observed when handling an assembly which contains these devices. CAUTION: Electrostatic energy is produced when two insulating materials are rubbed together. A person wearing rubber-soled shoes, walking across a nylon carpet or a waxed floor, can generate an extremely large electrostatic charge. This effect is magnified during periods of low humidity. Semiconductor devices such as integrated circuits, field-effect transistors, thyristors and Schottky diodes may be damaged by this high voltage unless adequate precautions are taken. Electrical discharging of personnel Personnel should be electrically discharged by a suitable grounding system (e.g., anti-static mats, grounding straps) when removing an assembly from the transmitter, and while handling the assembly for maintenance procedures. Handling/Storage An assembly should be placed in an anti-static bag when it is not installed in a host transmitter, or when it is not undergoing maintenance. Electronic components should be stored in anti-static materials. Tools/Test equipment Testing and maintenance equipment including soldering and unsoldering tools should be suitable (i.e., grounded tip) for contact with static sensitive semiconductor devices. Stress current protection Every precaution should be taken to ensure the static sensitive semiconductor devices are protected from unnecessary stress current. This is achieved by ensuring that current is not flowing when an electrical connection is broken, and that voltages are not present on external control/monitoring circuits when they are connected. Issue Page -3

24 Responding to alarms Identifying an alarm You can identify an alarm locally by viewing the front panel (see Front panel alarm checks ) or remotely by viewing the AUI s Transmitter Status page (see AUI Transmitter status page checks on page -6). Front panel alarm checks There two ways to check for alarms on the front panel: Alarm/status LEDs View alarms screen - see page -5 Alarm/status LEDs There are four LEDs on the left-hand side of the LCD display that provide information about the operational status of various sections of the transmitter - Exciter, Power Amplifier, Output Network and Power Supply (see Figure.). The LEDs can glow green, amber or red. Typically, green indicates normal operation, amber indicates a warning, and red indicates a fault or error. Figure.: Alarm/Status LEDs Exciter Power Amplifier Output Network Power Supply When an LED is: green - transmitter is on, with no known faults. amber - a fault is present that may cause a reduction in RF power, but the transmitter is still producing RF power. red - a fault is present and the transmitter is not producing RF power. When a fault is present, the transmitter may still produce an RF output. In this case, or if the transmitter has shut down, you should schedule and commence more in-depth fault diagnosis. See View alarms screen on page -5. Page -4 Issue

25 Responding to alarms View alarms screen If an alarm exists and is currently being recognized by the transmitter system, it is displayed in the View Alarms screen (Main Menu -> View Status -> View Alarms) of the front panel Display (see Figure.). Figure.: View Alarms Screen Table. on page -8 contains a column for most alarms that can occur, sorted alphanumerically. The Description and Troubleshooting Action column provides a brief description of the alarm, troubleshooting tips and a cross-reference to more detailed troubleshooting, if applicable.. Scroll through the View Alarms screen to view the active faults.. Attempt to clear any latching alarms by pressing the checkmark button in the Main Menu -> Reset Alarms screen. If the alarm persists, it will not clear from the display. 3. Locate the alarm name in Table. on page -8 to determine the cause of the alarm and perform any recommended procedures in the Description and Troubleshooting Action column. This may also lead to replacing a suspect PWB, power supply or fan, as detailed in Replacing a suspect PWB, power supply or fan on page -7. NOTE: Before undertaking any troubleshooting, record all meter readings and note if any other alarms are displayed on the View Alarms page. Record all alarms. NOTE: Table. on page -8 contains a column for most Alarms that can occur, sorted alphanumerically for each sub-system, including both the names displayed on the AUI and, if different, the front panel UI (in parentheses). The Description and Troubleshooting Action column provides a brief description of the alarm, troubleshooting tips and a cross-reference to more detailed troubleshooting, as applicable. 4. If troubleshooting and subsequent replacement of a suspect PWB or module causes the alarm to disappear from the View Alarms screen, the alarm has been successfully cleared. If the alarm does not remove the fault condition, contact Nautel. Issue Page -5

26 Responding to alarms AUI Transmitter status page checks If an alarm exists and is being recognized by the transmitter, it is displayed under the Alarms tab of the transmitter status page (see Figure.3). The Device name indicates the sub-system origin of the alarm. The sub-systems that can be displayed are: Controller: All alarms in this sub-system apply to the controller. Exciter: All alarms in this sub-system apply to the exciter. Figure.3: Transmitter Status Page. If an alarm exists, the Status button at the bottom of the AUI display will be red. Click the Status button to go to the Transmitter Status page (see Figure.3). View the list of active faults by pressing the Alarms tab. Alarms are listed by their origin (Device column), then by name (Alarm column), and then by severity [ = low (RF output not affected), 5 = medium (RF output is reduced), 0 = high (RF output is inhibited); see Level column].. Attempt to clear any latching alarms by pressing the Reset button on the bottom banner of the page. If the alarm persists, it will not be cleared from the display. Page -6 Issue

27 Responding to alarms 3. Locate the alarm name in Table. on page -8 to determine the cause of the alarm and perform any recommended procedures in the Description and Troubleshooting Action column. This may also lead to replacing a suspect PWB, power supply or fan, as detailed in Replacing a suspect PWB, power supply or fan on page -7. NOTE: Table. on page -8 contains a column for most Alarms that can occur, sorted alphanumerically for each sub-system, including both the names displayed on the AUI and, if different, the front panel UI (in parentheses). The Description and Troubleshooting Action column provides a brief description of the alarm, troubleshooting tips and a cross-reference to more detailed troubleshooting, as applicable. 4. If troubleshooting and subsequent replacement of a suspect PWB or module causes the alarm to disappear from the Transmitter Status page, the alarm has been successfully cleared. If the fault condition does not clear, contact Nautel. NOTE: Before undertaking any troubleshooting, record all AUI meter readings and note if any other alarms are displayed on the Transmitter Status page. Record all alarms. The most convenient way to do this is by using a web browser over a LAN connection to save screen shots of critical status, meter and alarm pages. From the System Review page, press the information (!) button for each sub-device (Controller and Exciter) to view (and save) detailed information (see Viewing real-time meters on page -3 of the Operations and Maintenance Manual).. Issue Page -7

28 Responding to alarms Table.: Troubleshooting Alarms Alarm Name AUI and (Front Panel) +.V Supply Fail (+.V Fail) +.8V Supply Fail (+.8V Fail) Front Panel LED (color) PS (red) PS (red) Description and Troubleshooting Action This alarm occurs if the +. V supply on the exciter/control PWB (A) is outside of its acceptable voltage range (between +. V and +.3 V). The VS.5 takes no action on this alarm. Check for a +5V Supply Fail alarm: If present, follow the associated troubleshooting procedure. If not present, use a digital multimeter to measure between TP5 (+. V) and TP6 (ground) of the exciter/control PWB. If the measured value is within the acceptable range, suspect the sampling circuitry on the exciter/ control PWB (A). If not, use a digital multimeter to measure between TP7 and TP6 (ground). The measured voltage should be between +4.5 V and +5.5 V. If the measured voltage is within the acceptable range, the power supply circuitry on the exciter/control PWB has failed. Replace the exciter/control PWB (see Exciter/ Control PWB Replacement on page -40). If not, check ribbon cable W4 for damage, and verify connectors W4P and W4P are properly seated in AJ and AJ6 respectively. If there are no visible problems with the ribbon cable, contact Nautel for further support. This alarm occurs if the +.8 V supply on the exciter/control PWB (A) is outside of its acceptable voltage range (between +.6 V and +.0 V). The VS.5 takes no action on this alarm. Check for a +3.3V Supply Fail alarm: If present, follow the associated troubleshooting procedure. If not present, use a digital multimeter to measure between TP4 and TP6 of the exciter/control PWB. If the measured value is within the acceptable range, suspect the sampling circuitry on the exciter/control PWB. If not, the power supply circuitry has failed on the exciter/control PWB. If necessary, replace the exciter/control PWB (see Exciter/Control PWB Replacement on page -40). Page -8 Issue

29 Responding to alarms Alarm Name AUI and (Front Panel) +5V Supply Fail (+5V Fail) -5V Supply Fail (-5V Fail) Front Panel LED (color) PS (amber) PS (amber) Description and Troubleshooting Action This alarm occurs if the +5 V supply from the PS distribution PWB (A) is outside of its acceptable voltage range (between +3.5 V and +6.5 V). The VS.5 takes no action on this alarm. Check for a +48V Supply Fail alarm: If present, follow the associated troubleshooting procedure. If not present, use a digital multimeter to measure between TP (+5 V) and TP3 (ground) of the PS distribution PWB. If the measured value is not within the acceptable range, the power supply circuitry on the PS distribution PWB has likely failed. If the measured value is within the acceptable range, check ribbon cable W for damage and that connectors WP and WP are properly seated in AJ and AJ7 respectively. If there are no visible problems with the ribbon cable, suspect the sampling circuitry on the PS distribution PWB. If necessary, replace the PS distribution PWB (see PS Distribution PWB Replacement on page -43). If the alarm persists after replacing the PS distribution PWB, suspect the exciter/control PWB (A). This alarm occurs if the -5 V supply on exciter/control PWB (A) is outside of its acceptable voltage range (between -3.5 V and -6.5 V). The VS.5 takes no action on this alarm. Check for a +5V Supply Fail alarm: If present, follow the associated troubleshooting procedure. If not present, use a digital multimeter to measure between TP3 and TP (ground) of the exciter/ control PWB. If the measured value is within the acceptable range, suspect the sampling circuitry on the exciter/control PWB. If not, use a digital multimeter to measure between TP and TP6 (ground). The measured voltage should be between +3.5 V and +6.5 V. If the measured voltage is within the acceptable range, the power supply circuitry on the exciter/control PWB has failed. Replace the exciter/control PWB (see Exciter/Control PWB Replacement on page -40). If not, check ribbon cable W4 for damage and that connectors W4P and W4P are properly seated in AJ and AJ6 respectively. If there are no visible problems with the ribbon cable, contact Nautel for further support. Issue Page -9

30 Responding to alarms Alarm Name AUI and (Front Panel) +3.3V Supply Fail (+3.3V Fail) +48V Supply Fail (+48V Fail) Front Panel LED (color) PS (red) PS (red) Description and Troubleshooting Action This alarm occurs if the +3.3 V supply on the exciter/control PWB (A) is outside of its acceptable voltage range (between +3.0 V and +3.6 V). The VS.5 takes no action on this alarm. Check for a +5V Supply Fail alarm: If present, follow the associated troubleshooting procedure. If not present, use a digital multimeter to measure between TP3 (+3.3 V) and TP6 (ground) of the exciter/control PWB. If the measured value is within the acceptable range, suspect the sampling circuitry on the exciter/ control PWB. If not, use a digital multimeter to measure between TP7 and TP6 (ground). The measured voltage should be between +4.5 V and +5.5 V. If the measured voltage is within the acceptable range, the power supply circuitry on the exciter/control PWB has failed. Replace the exciter/control PWB (see Exciter/ Control PWB Replacement on page -40). If not, check ribbon cable W4 for damage and that connectors W4P and W4P are properly seated in AJ and AJ6 respectively. If there are no visible problems with the ribbon cable, contact Nautel for further support. This alarm occurs if the output of the +48 V power supply (U4) is outside of its acceptable voltage range (between +43 and +53 V). The VS.5 takes no action on this alarm. Use a digital multimeter to measure between +V and -V of the +48 V power supply. If the measured value is not within the acceptable range, replace the +48 V power supply (see +48 V Power Supply Replacement on page -35). If the measured value is within the acceptable range, use a digital multimeter to measure the voltage between TP4 (+48V) and TP3 (ground) on the PS distribution PWB (A). If the measured value is not within the acceptable range, suspect the connection between the +48V power supply and the PS distribution PWB, and contact Nautel for further assistance. If the measured value is within the acceptable range, check ribbon cable W for damage and that WP and WP are properly seated in AJ and AJ7 respectively. If there are no visible problems with the ribbon cable, suspect the sampling circuitry on the PS distribution PWB. If necessary, replace the PS distribution PWB (see PS Distribution PWB Replacement on page -43). If the alarm persists after replacing the PS distribution PWB, suspect the exciter/control PWB (A). Page -0 Issue

31 Responding to alarms Alarm Name AUI and (Front Panel) +5V Supply Fail (+5V Fail) All Power Amplifiers Inactive (All PAs Inactive) Analog Audio Left Low (Anlg Left Aud Low) Analog Audio Right Low (Anlg Right Aud Low) Front Panel LED (color) PS (red) PA (red) Exciter (amber) Exciter (amber) Description and Troubleshooting Action This alarm occurs if the +5V-B supply from the PS distribution PWB (A) is outside of its acceptable voltage range (between +4.5 and +5.5 V). The VS.5 takes no action on this alarm. Check for +48V Supply Fail alarm: If present, follow the associated troubleshooting procedure. If not present, use a digital multimeter to measure between TP0 (+5V-B) and TP8 (ground) of the PS distribution PWB. If the measured value is not within the acceptable range, the power supply circuitry on the PS distribution PWB has failed. If the measured value is within the acceptable range, check ribbon cable W for damage and that WP and WP are properly seated in AJ and AJ7 respectively. If there are no visible problems with the ribbon cable, suspect the sampling circuitry on the PS distribution PWB. Replace the PS distribution PWB (see PS Distribution PWB Replacement on page -43). If the alarm persists after replacing the PS distribution PWB, suspect the exciter/control PWB (A). This alarm indicates that all of the PAs in the system or all of the power supply modules in the system have failed simultaneously; therefore PA failure alarms or power supply module related alarms should also be present. If there are power supply module related alarms present, or an IPA Output Low alarm, follow the associated troubleshooting procedure. If there are no power supply module related alarms, with RF turned on, use a digital multimeter to measure the voltage between pad V and pad W on any PA. If the voltage does not fall within an acceptable range (between.3 V and 3 V), suspect the exciter/control PWB (A). If the voltage does fall in the acceptable range, perform the PA resistance checks on page -30. If there is no problem found with any of the PAs, or the alarm still persists after replacing all of the damaged PAs, suspect the PS distribution PWB (A). This alarm indicates the analog left audio input level is too low or is not applied. The VS.5 takes no action on this alarm. This alarm indicates the analog right audio input level is too low or is not applied. The VS.5 takes no action on this alarm. Issue Page -

32 Responding to alarms Alarm Name AUI and (Front Panel) ARM Network Down ARM Not Booted ARM Not Responding Front Panel LED (color) Exciter (amber) Exciter (amber) Exciter (amber) Description and Troubleshooting Action This alarm indicates that the microcontroller that runs the remote interfacing applications (ARM) is unable to aquire an IP address. When this alarm is present, it will not be possible to access any of the remote functionality. Check that the Ethernet cable is properly connected to AJ8A on the rear of the transmitter. If the alarm is still present see Network setup on page -64 of the Operations and Maintenance Manuals for information on setting up the network connection. This alarm indicates that the microcontroller that runs the remote interfacing applications (ARM) is not yet running. This alarm should only be present when the transmitter is first turned on or after the transmitter's ac power has been cycled. This alarm indicates that the microcontroller that runs the remote interfacing applications (ARM) is not communicating with the transmitter s primary microcontroller (DSP). If the watchdog function is enabled, the DSP will automatically reset the ARM. If this alarm persists for more than 0 minutes, try cycling power (off, then on) to the transmitter. If the alarm persists, replace the exciter/control PWB (A) if necessary (see Exciter/Control PWB Replacement on page -40). Audio Loss Exciter (red) This alarm, enabled by the user, indicates that the exciter s audio modulation level is below the level specified in the dead air settings of the active preset (see Audio Loss on page -54 of the Operations and Maintenance Manuals to enable/disable this alarm and to configure the resulting action). Depending on the setting, this alarm could trigger a preset change, inhibit RF or have no effect (alarm only). Check the appropriate program input(s) and the dead air setting for the preset. Audio Shutdown Composite Audio Low (MPX Aud Low) Exciter (red) Exciter (amber) This alarm occurs if the exciter s audio processing and FM modulation code is shut down. Should display only during a software upgrade. This alarm indicates the composite audio input level is too low. The VS.5 takes no action on this alarm. Page - Issue

33 Responding to alarms Alarm Name AUI and (Front Panel) CPLD Version Mismatch (CPLD Ver Mismatch) Cutback Active Digital Audio Low (Digital Aud Low) Discharging PA Volts (Discharging PA V) Front Panel LED (color) Exciter (red) Output Network (amber) Exciter (amber) PS (red) Description and Troubleshooting Action This alarm indicates that the CPLD version installed on the transmitter does not match the version expected to be seen by the version of code installed on the DSP. The VS.5 will not be able to turn RF on. Contact Nautel for further assistance. This alarm occurs whenever the transmitter experiences a cutback. A cutback (reduction in power) occurs when repeated shutback alarms occur within a prescribed time period. Shutbacks occur when the transmitter's peak reflected power exceeds : due to a transient SWR condition (arc or lightning) within the output transmission line or antenna system. The transmitter shuts back and recovers to a series of cutback levels (depending on the severity of the alarm), with each level being a /8th reduction in power from the previous cutback level, starting from the preset setpoint. Inspect the output transmission line for punctures or damage. After repairing damage, or if no damage is found, attempt to reset the latched condition [using the remote AUI s Reset button (see Reset: on page -4 of the Operations and Maintenance Manual) or using the local front panel display (see Resetting alarms on page -57 of the Operations and Maintenance Manual)]. If no damage can be found, suspect a fault with the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). This alarm indicates the corresponding digital input level is too low and is typically accompanied by a SRC Unlock alarm (see its description and troubleshooting action). If no accompanying SRC alarm exists, suspect a problem with the external audio processor or studio feed. The VS.5 takes no action on this alarm. This alarm occurs when the transmitter has initiated a shutback sequence, and residual PA voltage energy stored in the capacitors in the power supplies and PAs is being discharged. During a shutback sequence, the RF drive to the PAs is turned off immediately after the event, and this occurs faster than the power supply modules can be inhibited. Therefore, PA voltage is still being applied to the capacitors with no drive to discharge the energy. To discharge the stored energy from the capacitors, the PA bias is increased to a discharge level after the power supplies have been inhibited. This causes the stored energy to be dissipated through dc current in the FET. This alarm should only occur with a Residual PA Volts Present alarm. See Residual PA Volts Present alarm for more information. Issue Page -3

34 Responding to alarms Alarm Name AUI and (Front Panel) Entered Firmware Upgrade (Exc Firmware Upgr) External Interlock Open (External Interlock) Fan - 7 Fail Forward Power Limiting (Fwd Power Limiting) Front Panel LED (color) Exciter (red) Exciter (red) Output Network (amber) Output Network (amber) Description and Troubleshooting Action This alarm occurs when the exciter is in firmware upgrade mode. It should only be displayed during a transmitter software upgrade. This alarm occurs when the external interlock input wired to the exciter/control PWB (A) is open. The VS.5 will not be able to enable its RF output. Check the interlock connection between AJA-9 and AJA-0 on the rear of the transmitter. If the interlock connection is intact, check that all external interlock switches are closed. If no problem is found with the connection at the transmitter or any of the external interlock switches, suspect a problem with the interlock circuitry on the exciter/control PWB (A). This alarm occurs if the speed of one of the transmitter's cooling fans is below 3000 RPM (half of its nominal value of 6000 RPM). If any of fans 3 through 7 fail, the VS.5 will reduce its maximum power setting based on the number of fan failures that have occurred (see Table. on page -6). If either fan or fail, the VS.5 takes no action (no effect on the RF output). If the alarm occurs for fans or, check the connection between the indicated fan and the PS distribution PWB (A). If the alarm occurs for fans 3, 4, 5, 6 or 7, check the connection between the indicated fan and the splitter PWB (A4). If these connections look OK, replace the indicated fan (see Cooling fan replacement - fans 3 (B3) through 7 (B7) on page -36). If the alarm still occurs after the fan has been replaced, suspect the PS distribution PWB for fans or and suspect the exciter/control PWB (A) for fans 3 through 7. When the High Forward Power alarm is active, the Forward Power Limiting alarm occurs if its associated threshold is exceeded (.063 times the maximum power setting; 976 W). The transmitter will fold back the forward power each time the threshold is exceeded. This alarm occurs only if the exciter ALC cannot respond fast enough to transmitter load changes. Inspect the antenna network attached to the transmitter. If there are no major issues with the antenna network that would cause an impedance change (icing for example) suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45) Output power probe PWB replacement on page -37. Page -4 Issue

35 Responding to alarms Alarm Name AUI and (Front Panel) Forward Power Low (Fwd Power Low) Forward Power Shutdown (Fwd Power Shutdown) Forward Power Very Low (Fwd Power Very Low) High Forward Power (High Fwd Power) High Reject Front Panel LED (color) Output Network (amber) Output Network (red) Output Network (amber) Output Network (amber) Output Network (amber) Description and Troubleshooting Action This alarm occurs if the transmitter's average forward power falls below the low forward power threshold (defaulted to 50% of the preset power level and is user adjustable) due to PA failures, fan failures, SWR foldback or a pre-amp/ipa failure. The VS.5 takes no action on this alarm. Check for associated alarms, and follow the associated troubleshooting procedure if present. If no other alarms are being indicated, with RF turned on, use a digital multimeter to measure the voltage between pad V and pad W on any PA. If the voltage does not fall within an acceptable range (between.3 V and 3 V), suspect the exciter/control PWB (A). If the voltage is within this range, suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). This alarm occurs if the transmitter tries to reduce the forward power below minimum (64 W) due to repeated Forward Power Limiting alarms. The transmitter latches off. See Forward Power Limiting for troubleshooting tips. This alarm occurs if the transmitter's average forward power falls below the very low forward power threshold (defaulted to.5% of the preset power level and is user adjustable) due to PA failures, fan failures, or SWR foldback. The VS.5 takes no action on this alarm. See Forward Power Low for troubleshooting tips. This alarm occurs if the transmitter's average forward power exceeds the high forward power threshold (.036 times the maximum power setting; 90 W). This alarm occurs only if the exciter ALC cannot respond fast enough to transmitter load changes. The VS.5 takes no action on this alarm. Check for associated alarms and follow the associated troubleshooting procedure, if present. If no other alarms exist, inspect the antenna network attached to the transmitter. If there are no major issues with the antenna network that would cause an impedance change (icing for example) suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). This alarm occurs if the control system determines that the calculated power in any reject resistor exceeds the high reject power threshold (30 W). The VS.5 takes no action on this alarm. Check for associated alarms, and follow the associated troubleshooting procedure if present. Typically, high reject power is the result of a PA failure or removal. If no other alarms are being indicated, contact Nautel for further support. Issue Page -5

36 Responding to alarms Alarm Name AUI and (Front Panel) High SWR High SWR Shutdown Insufficient Fans Active (Insuf. Fans Active) Front Panel LED (color) Output Network (amber) Output Network (red) Output Network (red) Description and Troubleshooting Action This alarm occurs if the transmitter's average reflected power exceeds the high SWR threshold (7 W). The VS.5 takes no action on this alarm. Inspect the antenna and transmission line system for damage or de-tuning. If there are no major issues with the antenna network that would cause an impedance change (icing for example), suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). This alarm occurs if the transmitter tries to reduce the forward power below a level that is equivalent to a 3: VSWR (forward power of 4 W) at the SWR Foldback threshold (reflected power of 03 W) due to a gradually degrading load match. This alarm causes the transmitter to latch off. Inspect the antenna and transmission line system for damage or de-tuning. If there are no major issues with the antenna network that would cause an impedance change (icing for example), suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). This alarm indicates that the fans in the transmitter s RF power stage are not running. This alarm causes the transmitter to shut down, and clears when the system detects a running fan in the RF power stage. See Fan Fail alarm for troubleshooting information. IPA Fail PA (red) This alarm occurs if the IPA Output Low alarm is present and the measured IPA current is below 5 ma. The VS.5 takes no action on this alarm. See IPA Output Low for troubleshooting tips. IPA Output High PA (red) This alarm occurs if the pre-amp/ipa PWB's (A5) forward power is greater than the IPA Output High threshold (36 W). If this condition persists, replace the pre-amp/ipa PWB (A5) (see Preamp/IPA PWB replacement on page -3). The VS.5 takes no action on this alarm. If this alarm persists after replacing the preamp/ipa PWB, suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45) or the exciter/control PWB (A) (see Exciter/Control PWB Replacement on page -40). Page -6 Issue

37 Responding to alarms Alarm Name AUI and (Front Panel) IPA Output Low Low Backup Battery Front Panel LED (color) PA (red) Exciter (amber) Description and Troubleshooting Action This alarm occurs if the pre-amp/ipa PWB's (A5) forward power is less than the IPA Output Low threshold (4.4 W). This alarm causes the controller to limit the PA voltage to 30 V. Check for a +48V Supply Fail alarm and follow the associated troubleshooting procedure if present. IPA Fail and Pre-amp Fail alarms may also be present. If no associated alarms are present, turn RF off and run the bias routine in the front panel s Main Menu -> System Settings -> Calibration menu. If the alarm persists, enable RF and use a digital multimeter to measure the voltage between pad B on pre-amp/ipa PWB (pre-amp bias) and chassis (ground) and also between pad C on pre-amp/ipa PWB (IPA bias) and chassis (ground). If the voltage is less than V at either of these points, suspect the exciter/control PWB (A). If the voltage is greater than V at both of these points, use a digital multimeter to measure between pad E (IPA volts) on the pre-amp IPA PWB and chassis (ground). If the measured voltage is not within and aceptable range (between +43 V and +48 V), with ac power off, perform a continuity check across F of the PS distribution PWB (A). If the measurement is greater than Ω, replace the fuse (Nautel Part # FA57 in the ancillary kit). If the measurement is less than Ω, or replacing the fuse does not clear the alarm, replace the pre-amp/ipa PWB (A5) (see Pre-amp/IPA PWB replacement on page -3). If the voltage on pad E is acceptable, use a digital multimeter to measure between pad D (pre-amp volts) on the preamp IPA PWB and chassis (ground). If the measured voltage is not within and aceptable range (between +43 V and +48 V), replace the pre-amp/ipa PWB (A5) (see Pre-amp/IPA PWB replacement on page -3). If the voltage is acceptable, or replacing the pre-amp/ipa PWB PWB does not clear the alarm condition, suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45) or the exciter/control PWB (A) (see Exciter/Control PWB Replacement on page -40). This alarm occurs if the backup battery voltage falls below an acceptable level (.7 V). The VS.5 takes no action on this alarm. Use a digital multimeter to measure the battery voltage (with ac power on). If the battery voltage is low, replace the battery. If battery voltage is OK, cycle ac power (off, then on). If the alarm does not clear, suspect the exciter/control PWB (A). Issue Page -7

38 Responding to alarms Alarm Name AUI and (Front Panel) Missing Preset (Exc Missing Preset) Need Reboot for Settings (Exc Need Reboot) Front Panel LED (color) Exciter (red) Exciter (red) Description and Troubleshooting Action This alarm indicates that there are no presets programmed into the transmitter. In this state, the transmitter s front panel UI will default to the first time startup screen (see Figure 8. on page 8- of the Installation Manual) and the user will not be able to enable RF without first programming a preset. This alarm indicates that exciter setup changes have been made, typically via the Hardware Configuration page of the AUI. Typically, the DSP will reboot itself automatically; however, if this alarm persists for more than five minutes, cycle the transmitter s ac power (off, then on) to store the changes. No PPS Exciter (amber) This alarm occurs if the pilot phase locking to PPS is enabled and the PPS signal is not present. Check the PPS input. If there are no problems with the PPS signal and connection, suspect the exciter/control PWB (A).The VS.5 takes no action on this alarm. No External 0 MHz (Exc No Ext 0MHz) No Internal 0 MHz Exciter (amber) Exciter (red) This alarm occurs if frequency locking to an external 0 MHz souce is enabled and no external 0 MHz is detected. The exciter will automatically switch over to the internal 0 MHz reference, and will continue to run. Check the 0 MHz input. If there are no problems with the 0 MHz signal and connection, suspect the exciter/control PWB (A). This alarm occurs if no 0 MHz clock is being detected on the exciter/control PWB (A). This alarm will cause the transmitter to shut-down and the exciter/controller PWB may not be running. Replace the exciter/control PWB (see Exciter/Control PWB Replacement on page -40). Page -8 Issue

39 Responding to alarms Alarm Name AUI and (Front Panel) Front Panel LED (color) Description and Troubleshooting Action PA - 4 Fail PA (amber) This alarm occurs if the dc input current for the indicated PA has fallen below a predetermined threshold (typically less than 50% of the average PA current of the operational PAs, or below 500 ma, whichever is lower). This may be caused by a cabling fault on the PA, loss of PA voltage or bias, or a defective FET. The transmitter's output power will be reduced (see Table. on page -6) and this condition could cause Per PA Foldback and Reject Foldback alarms. Check for an All Power Amplifiers Inactive alarm and follow the associated troubleshooting procedure if present. If the All Power Amplifiers Inactive alarm is not present, perform the PA resistance checks on page -30. If there is no problem found with the PAs, or the alarm still persists after replacing the PA, suspect the PS distribution PWB (A). PA Over Temperature (PA Over Temp) PA Pwr Foldback PA (red) Output Network (amber) This alarm occurs when the temperature as measured by RT or RT exceeds 85 C (85 F). This alarm will cause the transmitter to shut down and latch off. Check for Fan Fail alarms and follow the associated troubleshooting procedure if present. If no Fan Fail alarms are present, check the transmitter's air filter and clean or replace as required (see Section 3, Routine maintenance of the Operations and Maintenance Manual). If the alarm persists, suspect the exciter/control PWB (A). This alarm occurs if the control system determines that the calculated dissipation in any FET on a PA is above the high dissipation threshold (300 W), or the forward power being asked for out of an individual PA [calculated as (output power - combiner losses) / number of active PAs in the system] is above the PA output high threshold (850 W). The forward power of the transmitter will be limited to a level such that neither of these thresholds are exceeded. Check for associated alarms. Typically, the assertion of this alarm is the result of a PA failure or removal, or a high SWR condition. If no other alarms are being indicated, contact Nautel for further support. PA Volts Fail PS (amber) This alarm is for indication only, and occurs when the voltage output by the power supply module does not match what the controller thinks it should be based on the control signal it is sending to the power supply module. No action is taken on this alarm. This alarm may show up when turning RF on or off. Issue Page -9

40 Responding to alarms Alarm Name AUI and (Front Panel) Front Panel LED (color) Description and Troubleshooting Action Pilot Unsync Exciter (amber) This alarm occurs if there is no synchronization between the 0 MHz and PPS signals. It may indicate that the GPS receiver is not detecting a signal. Check the GPS receiver and antenna.the VS.5 takes no action on this alarm. PLL Unlock Exciter (red) This alarm indicates that the exciter s master clock is not locked. Possible causes are an out-of-range 0 MHz input or a hardware failure on the exciter/control PWB (A). The VS.5 s RF output is inhibited. Preamp Fail PA (red) This alarm occurs if the IPA Output Low alarm is present and the measured pre-amp current is below 7.5 ma. The VS.5 takes no action on this alarm. See IPA Output Low for troubleshooting tips.pre-amp/ipa PWB replacement - see page -3 PS A (or B or C) AC Fail PS A (or B or C) Fail PS (amber) PS (amber) This alarm occurs if power supply module A (U), B (U) or C (U3) is reporting an ac failure, indicating its ac input voltage is less than 75 V ac. The VS.5 will reduce its maximum power setting based on the number of power supply module failures that have occurred (see Table. on page -6). Check the ac voltage applied to the power supply module. If the ac voltage is acceptable, try replacing the indicated power supply module with a new module, or changing the position of the indicated power supply within the transmitter (see Power Supply Module Replacement on page - 34). If the fault moves with the power supply module, replace the power supply module. If the fault does not move with the power supply module, or if replacing it with a new power supply module does not clear the fault, suspect the PS distribution PWB (A). This alarm occurs if power supply module A (U), B (U) or C (U3) is reporting a PS failure, indicating its output voltage is outside of its acceptable range. The VS.5 will reduce its maximum power setting based on the number of power supply module failures that have occurred (see Table. on page -6). Try replacing the indicated power supply module with a new module, or changing the position of the indicated power supply within the transmitter (see Power Supply Module Replacement on page -34). If the fault moves with the power supply module, replace the power supply module. If the fault does not move with the power supply module, or if replacing it with a new power supply module does not clear the fault, suspect the PS distribution PWB (A) or the exciter/control PWB (A). Page -0 Issue

41 Responding to alarms Alarm Name AUI and (Front Panel) PS A (or B or C) Missing PS A (or B or C) Over Temperature (PS A Over Temp) Front Panel LED (color) PS (amber) PS (amber) Description and Troubleshooting Action This alarm occurs if power supply module A (U), B (U) or C (U3) is not being detected or has been removed. The VS.5 will reduce its maximum power setting based on the number of power supply module failures that have occurred (see Table. on page -6). If there is a power supply module in the position being indicated by the alarm, try replacing the indicated power supply module with a new module, or changing the position of the indicated power supply within the transmitter (see Power Supply Module Replacement on page -34). If the fault moves with the power supply module, replace the power supply module. If the fault does not move with the power supply module, or if replacing it with a new power supply module does not clear the fault, suspect the PS distribution PWB (A). This alarm occurs if power supply module A (U), B (U) or C (U3) is reporting a high temperature alarm, indicating its operating temperature has exceeded its internal threshold. The VS.5 will reduce its maximum power setting based on the number of power supply module failures that have occurred (see Table. on page -6). This alarm is most likely caused by a module fan failure or blockage. Allow the module to cool and attempt to reset the alarm. Verify the module turns on and its fan is operational. If the fan is not operational, inspect it for possible blockage. If a problem is found, replace the power supply module (see Power Supply Module Replacement on page -34). If there is no problem found, inspect the transmitter s air filter and clean or replace as required (see Section 3, Routine maintenance of the Operations and Maintenance Manual). If the alarm persists, try replacing the indicated power supply module with a new module, or changing the position of the indicated power supply within the transmitter (see Power Supply Module Replacement on page - 34). If the fault moves with the power supply module, replace the power supply module. If the fault does not move with the power supply module, or if replacing it with a new power supply module does not clear the fault, suspect the PS distribution PWB (A). Issue Page -

42 Responding to alarms Alarm Name AUI and (Front Panel) PS Current Foldback (PS Curr Foldback) Reject Foldback Reject Shutback Residual PA Volts Present (Residual PA V Pres) Front Panel LED (color) PS (amber) Output Network (amber) Output Network (red) PS (red) Description and Troubleshooting Action This alarm occurs if the control system determines that the calculated current output by any power supply module [calculated as (total current being supplied to PAs/number of power supply modules in system)] is above the high current threshold (45 A with two power supply modules removed and 40 A with two or three power supply modules present). The forward power of the transmitter will be limited to a level such that this threshold is not exceeded. Check for associated alarms, and follow the associated troubleshooting procedure if present. Typically, the assertion of this alarm is the result of a high SWR condition. If no other alarms are being indicated, suspect the PS distribution PWB (A). This alarm occurs if the control system determines that the calculated power in any reject resistor exceeds the reject power foldback threshold (400 W). The forward power of the transmitter will be limited to a level such that this threshold is not exceeded. This alarm should be accompanied by a High Reject alarm. Check for other associated alarms, and follow the associated troubleshooting procedure if present. Typically, high reject power is the result of a PA failure or removal. If no other alarms are being indicated, contact Nautel for further support. This alarm occurs if the control system determines that the calculated power in any reject resistor exceeds the reject power shutback threshold (480 W). This alarm will initiate an immediate shutdown of the transmitter's RF output. The transmitter will then attempt to turn RF on and increase the forward power of the transmitter to a level such that the reject foldback threshold is not exceeded. This alarm should be accompanied by a High Reject alarm and possibly a Reject Foldback alarm. Check for other associated alarms, and follow the associated troubleshooting procedure if present. Typically, a reject shutback is the result of a sudden PA failure. If no other alarms are being indicated, contact Nautel for further support. This alarm indicates that after the transmitter has turned off its RF output, it is unable to discharge the PA volts to a level that is below 3 V. This condition will not allow the transmitter to turn on its RF output; however the condition will be cleared once the PA volts reaches a level that is below 3 V. This condition will typically occur with a failed PA or power supply module. Check for associated alarms and follow the associated troubleshooting procedure, as applicable. If no associated alarms are present, suspect the PS distribution PWB (A) or the exciter/control PWB (A). Page - Issue

43 Responding to alarms Alarm Name AUI and (Front Panel) Front Panel LED (color) Description and Troubleshooting Action Running Bias Routine - This is an informational alarm only that is displayed when the bias routine has been initiated. Rebooted Exciter SCA Audio Low (SCA Aud Low) SCA Audio Low (SCA Aud Low) Exciter (red) Exciter (amber) Exciter (amber) This is an informational alarm only that is displayed when the watchdog timer reboots the transmitter s main microcontroller (DSP). Typically, this alarm will show up after an ac power interruption. This alarm indicates the SCA input level is too low or is not applied. The VS.5 takes no action on this alarm. This alarm indicates the SCA input level is too low or is not applied. The VS.5 takes no action on this alarm. SRC Unlock Exciter (amber) This alarm indicates that no valid AES/EBU stream data is being detected on the selected AES/EBU. The VS.5 takes no action on this alarm. SWR Foldback Output Network (amber) This alarm occurs if the transmitter's average reflected power exceeds the SWR foldback threshold (03 W) due to a gradually degrading load match. The forward power of the transmitter will be limited to a level such that this threshold is not exceeded. If the load match improves while the transmitter is producing RF output, the forward power will increase. If the transmitter folds back to a forward power that is equivalent to a 3: VSWR at the SWR Foldback threshold (forward power of 4 W), an SWR Shutdown alarm occurs. Inspect the antenna and transmission line system for damage or de-tuning. If there are no major issues with the antenna network that would cause an impedance change (icing for example), suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). Issue Page -3

44 Responding to alarms Alarm Name AUI and (Front Panel) SWR Shutback Front Panel LED (color) Output Network (red) Description and Troubleshooting Action This alarm occurs if the transmitter's reflected power suddenly exceeds the SWR shutback threshold, which is the reflected power that is equivalent to a : VSWR at max power (3 W) due to a transient SWR condition (arc or lightning) within the output transmission line or antenna system. Attempt to reset the latched condition by pressing Reset [using the remote AUI s Reset button (see Reset: on page -4 of the Operations and Maintenance Manual) or using the local front panel display (see Resetting alarms on page -57 of the Operations and Maintenance Manual)]. Inspect the output transmission line for punctures or damage. If no damage can be found, suspect the combiner interface PWB (A) (see Combiner Interface PWB Replacement on page -45). See also Cutback Active alarm. Transmitter RF Off - This alarm occurs if the transmitter is in an RF off state. Unsigned DSP Image (Exc Bad DSP Image) Exciter (red) This alarm indicates that the exciter is operating with unsigned code, but is otherwise operational. This alarm may only be displayed if the transmitter is operating with a beta version of factory software. Page -4 Issue

45 Responding to alarms Troubleshooting tips AUI lockup If the remotely accessed AUI screen stops responding, and subsequent attempts to re-access the AUI are unsuccessful, verify that all network settings are correct (see Network Setup in the Operations and Maintenance Manual). If all network settings are correct and the AUI continues to be inaccessible, perform the ARM Reset procedure in the Operations and Maintenance Manual. If the AUI is still inaccessible, try cycling (turn off, then on) the ac power. If the problem persists, contact Nautel for further assistance. Issue Page -5

46 Responding to alarms Operating with defective PAs or cooling fans It is permissible to operate the transmitter with multiple defective power amplifier PWBs or cooling fans. Table. shows the approximate remaining output power when power amplifiers (PAs) or cooling fans fail. NOTE: There are several combinations of PA, PS module or fan failures that can affect the RF output. Table. shows the maximum RF output power that can be expected for a given condition. In the event that PA, PS and fan failures occur simultaneously, the maximum RF output power is limited to the lowest maximum power of each individual condition. CAUTION: Defective PAs must remain installed in order for the transmitter to continue operating. Operation with removed PAs may result in an unstable RF output and possible damage to transmitter circuitry. Table.: Output Power Level vs. PA or Fan Failure PA PWB or Fan Failures Maximum RF Output Power (W) PA fan (B3 - B7) 500 (full power) PA fans (B3 - B7) 50 (half power) 3 PA fans (B3 - B7) 64 (minimum power) 4 PA fans (B3 - B7) 64 (minimum power) 5 PA fans (B3 - B7) 0 (RF output is inhibited until at least fan is replaced) PA PWB (A6 - A9) 780 PA PWBs (A6 - A9) between 340 and 475, depending on PA positions 3 PA PWBs (A6 - A9) 0 PS module (U, U or U3) 500 PS modules (U, U or U3) 800 Page -6 Issue

47 Responding to alarms Replacing a suspect PWB, power supply or fan Maintenance philosophy Maintenance on a VS.5 transmitter consists of replacing any of the PWBs, power supplies or fans identified in Table.3 on page -8. Special Tools and Test Equipment The following tools and test equipment are required to troubleshoot a VS.5 transmitter. Digital multimeter Torque screwdriver, capable of torquing up to. N-m (0 in.-lbs). Required for installing securing hardware for PA PWB FETs and power supply connections. Soldering iron and desoldering tool VS.5 station spares kit, if purchased (contains replacement PA PWBs, pre-amp/ipa PWBs and cooling fans) Electrical schematics in Section 5 of this manual. Mechanical drawings in Section 6 of this manual. Electrostatic Precautions The VS.5 transmitter contains semiconductor devices that are susceptible to damage from electrostatic discharge. Be sure to follow the electrostatic precautions in Electrostatic protection on page -3 at all times. Issue Page -7

48 Responding to alarms Preparation for replacing a PWB or module. Disable the VS.5 s RF output (RF off) and set its AC POWER switch to the off position. Disconnect all cabling from the rear of the VS.5, remove the VS.5 from its host cabinet and place the VS.5 on a suitable work surface.. Based on the alarm that prompted troubleshooting, replace the appropriate PWB, module or cooling fan (see the appropriate replacement procedure in Table.3 on page -8). NOTE: If a power amplifier (PA) failure occurs, you must replace the entire power amplifier PWB, rather than an individual FET. A spare PA PWB (NAPA3) is provided in the transmitter station spares kit, if purchased. To order a station spares kit contact Nautel. Failure to observe this recommendation may void your equipment warranty or cause further failures. Table.3: Replacement Procedures Module Replacement Procedure PA PWB See page -9 Pre-amp/IPA PWB See page -3 Power Supply Module See page V Power Supply See page -35 Cooling Fan (B3 through B7) See page -36 Cooling Fan (B and B) See page -38 Exciter/Control PWB See page -40 PS Distribution PWB See page -43 Combiner Interface PWB See page -45 Page -8 Issue

49 Responding to alarms PA PWB replacement See Figure MD- in the Mechanical Drawings section (Section 6) of this manual.. Remove the transmitter s bottom cover. Retain hardware for re-installation.. Before replacing a suspect PA PWB, verify the fault is with the suspect PA PWB by performing the continuity and resistance checks detailed in PA resistance checks on page -30. If you are prompted to replace a PA PWB, return to Step 3 of this procedure. 3. Unsolder and remove the five solder connections to the defective PA PWB. They include two 4 AWG links (to pads V and X), a white AWG wire (to pad U) and a black AWG wire (to pad T). If you are removing PA # 3 (A8), note that the black AWG wire is secured, using a terminal lug, to the front, left screw that secures A8 to the heat sink. 4. Remove the two #4 screws, split and flat washers securing the FET to the heat sink. 5. Remove the four M3 screws securing the PA PWB to the heat sink. Remove the PA PWB from the heat sink. Ensure that the silverstrate pads that were below the FETs have been removed from the heat sink. If necessary, use a knife blade to carefully pry the pads from the heat sink surface. 6. Clean the heat sink surface with a soft cloth and non-abrasive grease remover. Do not use any material that may scratch the heat sink surface. 7. Obtain the replacement NAPA3 PA PWB from the station spares kit, if purchased. NOTE: FETs are static sensitive. Handle the PA PWB in a static protected manner. 8. Install a new silverstrate pad (Nautel Part # HAK64, obtained from the station spares kit) between the FET (Q) and the heatsink. Issue Page -9

50 Responding to alarms 9. Secure the PA PWB on the module's heat sink using the four screws removed in Step 5. Ensure correct orientation (same as the adjacent PWB). Do not tighten the four screws at this time. CAUTION: When installing FET securing hardware, you can damage the FET case if you fully tighten one screw while the other is loose. Avoid this by alternately tightening the two screws. 0. Secure the FET (Q) with two # 4 screws, a mini-flat washer and a new split washer. Using a torque screwdriver, alternate tightening the left and right screws on each FET, a quarter turn at a time, until 6 inch-pounds (0.67 Newton-meters) of torque has been applied.. Tighten the four PWB screws.. Solder the wires removed in Step 3. If necessary, refer to Table 4.3, Wiring List - VS Transmitter for wiring details for A6 through A9. 3. Re-install the transmitter s bottom cover. 4. Re-install the transmitter in its host cabinet, reconnect all interconnect cables and restore operation by enabling ac and RF power. PA resistance checks. Using a digital multimeter, check the continuity across fuse F on the suspect PA PWB. If the measurement is an open circuit, replace the PA PWB (see PA PWB replacement on page -9). If the measurement is short circuit (near 0 Ω), proceed to Step.. Using a digital multimeter, measure the resistance between each gate lead of the FET and the metal flange of the FET. If the measurement is less than 8 kω, replace the PA PWB (see PA PWB replacement on page -9). If the measurement is between 8 kω and 7.5 kω, check the other PA PWBs for a failure. If none of the other PA PWBs have failed, replace the original suspect PA PWB. If the measurement is greater than 7.5 kω, proceed to Step 3. Page -30 Issue

51 Responding to alarms 3. Using a digital multimeter, check the continuity between each drain lead of the FET (positive meter probe) and the metal flange of the FET (negative meter probe). If the measurement is open circuit, the PA PWB is OK and does not require replacement. Continue troubleshooting and suspect a problem with an associated PWB. If the measurement is not open circuit, replace the PA PWB (see PA PWB replacement on page -9). Pre-amp/IPA PWB replacement See Figure MD- in the Mechanical Drawings section (Section 6) of this manual.. Remove the transmitter s bottom cover. Retain hardware for re-installation.. Unsolder and remove the six solder connections to the pre-amp/ipa PWB (A5). They include two white, 6 AWG wires (to pads D and E), three 4 AWG tinned copper jumpers (to pads A, B and C) and two 0 AWG tinned copper jumpers (to pads F and H). 3. Remove the two #4 screws, Belleville and flat washers securing each of the clamps that secure FETs Q and Q to the heat sink. 4. Remove the four M3 screws securing the pre-amp/ipa PWB to the heat sink. 5. Remove the pre-amp/ipa PWB from the heat sink, noting the orientation. 6. Clean the heat sink surface with a soft cloth and non-abrasive grease remover. Do not use any material that may scratch the heat sink surface. 7. Obtain the replacement NAPA8A pre-amp/ipa PWB from the station spares kit, if purchased. NOTE: FETs are static sensitive. Handle the pre-amp/ipa PWB in a static protected manner. Issue Page -3

52 Responding to alarms 8. Secure the pre-amp/ipa PWB on the heat sink using the four screws removed in Step 5, noting the correct orientation. Do not apply thermal compound under FETs Q and Q. Do not tighten the four screws at this time. CAUTION: When installing FET securing hardware, you can damage the FET case if you fully tighten one screw while the other is loose. Avoid this by alternately tightening the two screws. 9. Install FET clamps (Nautel Part # -5) on Q and Q, ensuring they are parallel to the heat sink. Loosely secure the FETs (Q and Q) with two #4 screws, a new Belleville washer (Nautel Part # HAJ59) and a flat washer (see Figure.4 on page -33). Turn screws until they barely put pressure on the clamp. 0. Using a torque screwdriver, alternate tightening the left and right screws on each FET clamp, a quarter turn at a time, until 5 inch-pounds (0.56 Newton-meters) of torque has been applied.. Tighten the four M3 PWB screws.. Solder the wires removed in Step. If necessary, refer to Section 4 of this manual for wiring details for A5. 3. Re-install the transmitter s bottom cover. 4. Remove the transmitter s top cover. Check the continuity across fuse F on the PS distribution PWB (A). If the resistance is greater than Ω, replace fuse F (Nautel Part # FA57, located in the ancillary kit) and re-install the transmitter s top cover. 5. Re-install the transmitter in its host cabinet and reconnect all interconnect cables. Enable ac power. 6. Run the Bias Routine in the front panel UI s System Settings -> Calibration menu. 7. Enable the transmitter s RF output (RF on). Page -3 Issue

53 Responding to alarms Figure.4: Pre-amp/IPA PWB mounting hardware SCREW NEW BELLEVILLE WASHER (HAJ59) FLAT WASHER FET CLAMPS (-5) Issue Page -33

54 Responding to alarms Power Supply Module Replacement See Figure MD- (top view) in the Mechanical Drawings section (Section 6) of this manual.. Remove the transmitter s top cover. Retain hardware for re-installation.. Remove the securing bracket from the front of the power supply module (U, U and U3) by removing two M3 screws in the top of the bracket and two M4 countersunk screws in each side of the transmitter chassis. Note the orientation of the bracket for installation of the new power supply module. Retain hardware. 3. Slide the power supply module toward the front of the transmitter to disengage it from its mating connector. 4. Remove the power supply module from the transmitter. 5. Locate or obtain a replacement power supply module (Nautel Part # UG69A). Reverse Step through Step 4 to reinstall the new power supply module. 6. Re-install the transmitter in its host cabinet, reconnect all interconnect cables and restore operation by enabling ac and RF power. Page -34 Issue

55 Responding to alarms +48 V Power Supply Replacement See Figure MD- (top view) in the Mechanical Drawings section (Section 6) of this manual.. Remove the transmitter s bottom cover. Retain hardware for re-installation.. Remove the two M3 screws and two countersunk M4 screws that secure the +48 V power supply (U4) (and its mounting bracket) to the transmitter. Retain hardware. 3. Remove the +48 V power supply from the transmitter and remove the mounting bracket for use with the new power supply. Note the orientation of each bracket for installation of the new power supply. 4. Disconnect wires # 0,,, 3 and 4 from the +48 V power supply s terminal block, noting their destinations. 5. Locate or obtain a replacement +48 V power supply (Nautel Part # UG75). Install the two mounting brackets on the new power supply and reverse Step through Step 4 to reinstall the new +48 V power supply. If necessary, refer to Section 4 of this manual for wiring details for U4. Torque all terminal connections on U4 to inch pounds (. Newton-meters). 6. Re-install the transmitter in its host cabinet, reconnect all interconnect cables and restore operation by enabling ac and RF power. Issue Page -35

56 Responding to alarms Cooling fan replacement - fans 3 (B3) through 7 (B7) See Figure MD- (bottom view) in the Mechanical Drawings section (Section 6) of this manual. CAUTION: Do not replace a cooling fan while ac power is applied to the transmitter. Failure to observe this could result in damage to the fan s associated tachometer circuitry.. Remove the transmitter s bottom cover. Retain hardware for re-installation.. Disconnect the fan mating plugs (B3P through B7P). 3. Slide the cooling fan bracket assembly out of the transmitter chassis (see Figure.5 on page -37). 4. Remove and retain all M3 screws and other hardware that secures the fans to the mounting brackets. Note the orientation of brackets and fans before disassembling. 5. Remove the clip-on ferrite (Nautel Part # LA5) from the fan that is being replaced. 6. Obtain a replacement fan (Nautel Part # ZAP4) from the station spares kit, if purchased, or a suitable equivalent (vendor part # is Sanyo Denki 9G0848G03). 7. Install the clip-on ferrite on the wiring for the new fan. Secure the ferrite using a tyrap (Nautel Part # HT9) on each side of the ferrite. See the other fans for reference. 8. Install the replacement fan, along with the other functional fans, on the mounting brackets using retained screws. 9. Re-install the cooling fan bracket assembly in the transmitter chassis. Keep the fan bracket level when installing in the transmitter. Failure to do so could cause the bracket the bind and break the plastic slides if excessive force is used. 0. Reconnect the fan mating plugs to the splitter PWB (A4). If necessary, refer to Table 4.4, Connector Mating Information - VS Transmitter for connector mating details for A4.. Re-install the transmitter s bottom cover.. Re-install the transmitter in its host cabinet, reconnect all interconnect cables and restore operation by enabling ac and RF power. Page -36 Issue

57 Responding to alarms Figure.5: Fan Bracket Removal B and bracket Remove front panel air filter to allow removal of B or B B and bracket B3 B4 B5 B6 B7 in bracket assembly Issue Page -37

58 Responding to alarms Cooling fan replacement - fans (B) and (B) See Figure MD- (bottom view) in the Mechanical Drawings section (Section 6) of this manual. CAUTION: Do not replace a cooling fan while ac power is applied to the transmitter. Failure to observe this could result in damage to the fan s associated tachometer circuitry.. Remove the transmitter s top cover. Retain hardware for re-installation.. Disconnect the associated fan mating plug (BP or BP). 3. Remove the front panel air filter to gain access to fan bracket securing hardware (see Replacing a damaged air filter on page 3- of the Operations and Maintenance Manual for instructions on removing and re-installing the air filter). 4. Remove three countersunk M4 screws securing the fan bracket to the transmitter chassis (see Figure.5 on page -37), noting there is one in the front and two on the sides. Remove the bracket, with fan, noting proper orientation for re-assembly. Retain hardware. 5. Remove and retain all M3 screws and other hardware that secures the fan to the mounting bracket. Note the orientation of the bracket and fan before disassembling. 6. Remove the clip-on ferrite (Nautel Part # LA5) from the fan that is being replaced. 7. Obtain a replacement fan (Nautel Part # ZAP4) from the station spares kit, if purchased, or a suitable equivalent (vendor part # is Sanyo Denki 9G0848G03). 8. Install the clip-on ferrite on the wiring for the new fan. Secure the ferrite using a tyrap (Nautel Part # HT9) on each side of the ferrite. See the other fans for reference. 9. Install the replacement fan on the mounting bracket using retained screws. 0. Re-install the cooling fan bracket assembly in the transmitter chassis using retained screws.. Reconnect the fan mating plug to its associated mate (BP to J5, BP to J6). If necessary, refer to Section 4 of this manual for connector mating details.. Re-install front panel air filter. Page -38 Issue

59 Responding to alarms 3. Re-install the transmitter s top cover. 4. Re-install the transmitter in its host cabinet, reconnect all interconnect cables and restore operation by enabling ac and RF power. Issue Page -39

60 Responding to alarms Exciter/Control PWB Replacement See Figure MD- (top view) in the Mechanical Drawings section (Section 6) of this manual. NOTE: The exciter/control PWB is static sensitive and must be handled in a static protected manner.. Remove the transmitter s top cover. Retain hardware for re-installation.. Disconnect all mating plugs from the exciter/control PWB (A), both inside the transmitter and at the rear of the transmitter. 3. At the rear panel, remove any securing hardware for connectors that protrude through the rear panel. Retain all hardware for re-installation. Locate the two DB-5 connectors (JA and JB) and the two DB-9 connectors (J5A and J5B) on the rear panel. Using a 5 mm nut driver or socket, remove the mounting nuts. Locate the AES/EBU XLR audio connector (J3) on the rear panel. Remove the two small pan-head Phillips screws. Remove the silver push button connector lock ("push" lever) on the XLR connector. Locate the HAS78 removal tool from the ancillary kit, provided with the transmitter. Follow the manufacturer's instructions in Figure.6 on page -4 to remove the push button. You will need access to the front and rear of the receptacle to remove it. 4. See Figure.7 on page -4. Remove the locking rings from five BNC connectors (J4A, J4B, J6A, J6B and J7). To remove the locking rings, use small 4-6 inch slip-jaw pliers. Gently loosen (do not tightly pinch or deform) each locking ring. Typically, half a turn with the pliers will loosen a locking ring enough to remove it by hand. Remove and retain the locking rings. 5. Remove the three small Phillips screws, which mount the front of the exciter/control PWB to the chassis, located along the edge of the exciter/control PWB. Retain hardware for reinstallation. 6. Cut tyraps securing ferrite L8. Remove the two metal clips that hold L8 together and remove the half of L8 that is closest to the exciter/control PWB. Page -40 Issue

61 Responding to alarms Figure.6: Removing the XLR connector s push lever Figure.7: Loosening the BNC connector s locking ring Issue Page -4