*~--1 CAB SIGNAL TEST SET SERVICE MANUAL U,& SIGNAL INC. A member ol the ANSALDO Group!>800 CorpotdlC nm,, P1lbbur1h P1\ 1;J JI AN SAL DO

Transcription

1 [t]unon SWTCH U,& SGNAL NC. A member ol the ANSALDO Group!>800 CorpotdlC nm,, P1lbbur1h P1\ 1;J J SERVCE MANUAL -6221,../ Operation, nstallation and Maintenance CAB SGNAL TEST SET ON-BOARD MODEL N *~--1 me'oo. ~ June, 1990 A-06/ A COPYUt,tll UNON WVlllll & \l(,na 1111( l JJN ll lj J\ U\A AN SAL DO Trasporli

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3 00UNON SWTCH UJ& SGNAL NC. A member of the ANSA.DO Group '1800 Curp1>r.1lt_ U11..,, P1thbuc._1h P1\ ')} j/ SERVCE MANUAL 6221 Operation, nstallation and Maintenance CAB SGNAL TEST SET ON-BOARD MODEL N June, 1990 A-06/ D0494A (Uf'YHl(,,tl l'j'ju. llfj10n \Wll( & \ll1nal f"(. l'hnlt!1 N 11\\ ANSALDO Trasport!

4 REVSON NDEX Revised pages of this manual are listed by page number and date of revision: Page No. Rev. Date Page No. Rev. Date Cab Signal Test Set

5 CONTENTS Section GENERAL NFORMATON 1. l NTRODUCTON 1.2 COMPONENTS l. 2.1 Housing l. 2.2 Printed Circuit Boards 1.3 Specifications NSTALLATON AND ADJUSTMENT 2.1 UNT SELECTON 2.2 MOUNTNG 2. 3 OPERATNG POWER AND SGNAL CONNECTONS 2.4 SENSTVTY CALBRATON /4 1-3/ OPERATON ;2 CONTROLS AND NDCATORS Operating Procedure Automatic Cycling Manual Cycling V v FUNCTONAL DESCRPTON 4.1 CONTROL OF POWER AND TEST SGNALS 4.2 SEQUENCNG OF CODE RATES 4.3 CODE OSCLLATON SOURCE 4.4 SAMPLE OPERATON: UNT N FELD MANTENANCE 5.1 GENERAL PROCEDURES 5.2 PERODC NSPECTON AND CALBRATON /2 5-1/2 5-1/2 V SHOP MANTENANCE 6.1 GENERAL 6.2 UNT FUNCTONAL TEST Required Test Equipment Test Set-Up Test Procedure Comments Procedure PCB TROUBLESHOOTNG General Detailed Circuit Descriptions Auto Code PCB 1 Auto Code PCB 2 Required Test Equipment Test Set-Up and Physical Check Test Procedure Comments Procedure i

6 CONTENTS (Cont'd) Section APPENDX A A. l A.2 A.3 A. 3.1 A.3.2 A.4 A.4.1 A.4.2 PARTS LST COMPLETE UNTS UNT ASSEMBLY AUTO CODE PCB 1 Unit/PCB Cross References Components AUTO CODE PCB 2 Unit/PCB Cross References Components A-2 A-2 A-4 A-4 A-4 A-6 A-6 A-6 Figure l A-1 A-2 A-3 LLUSTRATONS Cab Signal Test Set General Application High/Low Sensitivity Adjustment Potentiometers Cab Signal Test Set controls and ndicators Cab Signal Test Set Block Diagram Set-Up for General Test of unit Unit Test Waveform u Unit Test Waveform t2 Auto Code PCB 1 Schematic Diagram Auto Code PCB 2 Schematic Diagram Chassis Wiring PCB Test Waveforms Unit Assembly Auto Code PCB 1 Component Layout Auto Code PCB 2 component Layout Page / / / A-3 A-5 A-7/8 ii

7 SECTON GENERAL NFORMATON 1.1 NTRODUCTON The Cab Signal Test Set performs tests of on-board cab signaling equipment, and departure tests. t is designed to be permanently mounted in the cab of the locomotive and simulates inputs (to the cab signal equipment box) from the axle generator and receiver coils. The code rate and the two output levels of carrier can be used to troubleshoot or test "EL" coded cab signaling equipment. Figure 1-1 on the following page shows the general application of the Cab Signal Test Set. Six different versions of the Cab Signal Test Set are provided to accomodate different cab signal systems. These are listed in.the Table 1-1 following: Table 1-1. Cab Signal Test Set Output Options Unit Part No Carrier Freq. Code Rate (CPM) N Hz. 75, N Hz. 75, N Hz. 75, , 270, 410 N Hz. 75, , 270, 410 N Hz. 50, 75, , 270, 410 N Hz. 50, 75, , 270, 410 Cab signal systems are tested by inductively coupling the test signals into the receiver coils. This can be accomplished with permanently installed wayside loops or a loop mounted on the underside of the locomotive. However, this arrangement requires that testing be done at a fixed location where the test loop is permanently installed. Otherwise, a portable loop must be positioned under the receiver coils and connected to a portable test set. The Cab Signal Test Set is designed to remove the practical difficulties associated with this type of testing. The test set will verify a typical cab signaling system, complete with receiver coils, by injecting the test signal directly into the coils. The set's output incorporates a high impedance, electronically regulated current source, which simulates pick-up from the rails. ntegrated circuits are used to generate carrier and code frequencies, and an LED provides visual indication (flashing) of code rates. When power is applied, the test set will begin testing by generating the lowest code Frequency for a five second time period before automatically sequencing to the next higher code frequency. The set will continue to automatically sequence every five seconds to the next higher code. When the highest code rate is reached and five seconds has elapsed, the test set will automatically sequence back down through the code rates. When the lowest code rate has been reached and five seconds has elapsed, the test set will automatically generate uncoded continuous carrier. 6221, p. 1-1

8 ASPECT DSPLAY UNT 0 O r...~~~~~-1-~~~~~----,. 0 0 SMULATED RECEVER NPUT CAB SGNAL TEST SET 32V CAB SGNAL EQUPMENT BOX SMULATED RECEVER NPUT RECEVER COL SMULATED CODE NPUT RECEVER COL AXLE GENERATOR Figure 1-1. Cab Signal Test Set General Application 1.2 COMPONENTS l.2.l Housing The Cab Signal Test Set is contained in 2-piece steel case with a removable top cover. Two welded flanges permit suitable mounting in the cab of the locomotive. Operating power and signal outputs are connected through a 7-pin (male) threaded plug at one end of the housing. This connector is providen a f1~male plug and cable clamp at shipment. An open connector shell with protective cap is installed at the opposite end of the housing. This component allows access to an internal potentiometer for adjustment purposes. Test set controls and indicators include one 4PDT, spring-loaded, return-to-center toggle switch (HGH/OFF/LOW}, one SPDT toggle switch (AUTO/HOLD) and one LED (CODE NDCATOR). These are used to conduct and monitor the cab signal testing procedures. The unit cover also contains two banana jacks (CALBRATE) which allow measurement of the simulated coil output current (with respect to input current), without removing the top cover of the housing. 6221, p. 1-2

9 1.2.2 Printed Circuit Boards All functional electronics for the Cab Signal Test Set are contained on two printed circuit boards (PCB's): Auto Code PCB 1, and Auto Code PCB 2. These boards are stacked inside the housing on insulated spacers or stand-offs, with Auto Code PCB 2 on top. All external components (switches, jacks, connector, LED) are hard-wired to the PCB's on discrete turret lugs. Auto Code PCB 1 is used to create a cycle of ascending and descending binary numbers that are equivalent to speed codes from the axle generator. ts principle components include a 4541 clock oscillator C, which defines the five second peroid of each code cycle, a 4510 up/down counter C, which produces the binary equivalents of the increasing/descreasing code frequnecies, a bit magnitude comparator, which set the upper limit of the code rates, and a 4013 dual flip-flop C which (a) reverses the code cycle to the descending direction and (b) marks when the last (lowest) code rate has been run. Auto Code PCB 2 is used to produce the actual coded carrier signal, as calibrated by Auto Code PCB 1. ts principle components include a 4541 oscillator C, which develops the code rate of the test set output, a bit multiplexer, which converts the up/down binary codes (from Auto Code PCB 2), to single-bit outputs that calibrate the output of oscillator C, and another 4541 C that sets the fixed carrier frequency of the output. This PCB also includes separate transistors that (a) switch through the current of the test set output, and (b) drive the code rate LED. 1.3 Specifications Dimensions Cw/flanges): Weight: Mounting: Connections: Power nput: Output Options: L = 7-1/2", W = 4-1/2", H = 3-7/32" 3 lbs. Wall or equipment box, 2" x 6-3/4" centers with 5/16 mounting holes One 7-pin male plug, male thread barrel 32 Vdc, ±. 0.2 Vdc Refer to Table 1-1 on page , p. 1-3/4

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11 SECTON NSTALLATON AND ADJUSTMENT 2.1 UNT SELECTON Table 1-1 gives the carrier frequencies and code rates available with each of the six models of the Cab Signal Test Set. Make certain to install the correct unit for the particular cab signal system. f the carrier frequency does not match the frequency for the cab signal system, the system will not respond to the test output from the set. f the set generates a code rate not used by the cab signal system, erratic or misleading responses may be produced. f the unit does not generate a code rate that is used by the cab signal system, that rate cannot be verified. Connection of the wrong Cab Signal Test Set to a given cab signal equipment box will not cause equipment damage. 2.2 MOUNTNG The cab Signal Test should be mounted near the acknowledgement lever or switch so that the operator can easily reach both devices at the same time. During cab signal tests, the operator must be able to hold the HGH/OFF/LOW toggle switch in either position while also operating the acknowledgement control. The HGH/OFF/LOW switch is spring-loaded to return to the center position when the operator removes his hand. f the operator cannot hold over this switch, the set will not operate. f possible, the cab Signal Test Set should also be mounted near the main cab signal equipment Box, to minimize cable length and routing problems. Sufficient space should also be left around the durmny connector end of the housing, so that internal poteniometers can be easily adjusted with a screwdriver. 2.3 OPERATNG POWER AND SGNAL CONNECTONS The Cab Signal Test set receives its operating power from the cab signal 1?quipment box; a separate external power source is not required. Voltage positive and ground return is provided by two wires in the cabling between the test set and cab signal equipment box. Each Cab Signal Test box is provided a female plug connector, bushing and cable clamp. However, complete test set-to-signal system cable assemblies are not provided by US&S and standard assemblies. Contact US&S Engineering for special cable design and installation requirements not covered by these examples. 6221, p. 2-1

12 2.4 SENSTVTY CALBRATON Prior to using the Cab Signal Test Set, two potentiometers on Auto Code PCB 2 must be adjusted to make certain that the set generates simulated carrier signals at levels equivalent to those produced in the locomotive's receiver coils. This level is read on the two plug-in jacks on the front cover of the unit, and requires a Fluke 8000A multimeter (or equivalent) to read the respective voltages. A thin bladed screwdriver is also needed to adjust the potentiometers. The procedure is as follows: 1. Position locomotive over wayside test loop. 2. Check that the receiver coils are at the proper height above the rails, and adjust if necessary. 3. Adjust the rail current of the wayside test loop to the desired minimum level. 4. Measure and record the high and low voltages induced in the receiver coils with respect to the maximum and minimum current present in the rails. These voltages will be used to calibrate the test set. 5. On the test set attach the mutimeter + probe to the red CALBRATE jack, and the - probe to the black CALBRATE jack. 6. Remove the cap on the dummy connector at the top of the set and move the AUTO/HOLD switch to the AUTO position. 7. Turn on the cab signal system equipment box. This will apply 32 Vdc to the power circuit of the test set. 8. Hold the HGH/OFF/LOW switch in the LOW position and observe the ~ultimeter reading. The following tabulation indicates the low voltage range that should appear for each type of Cab Signal Test Set: Unit Part No. Low Voltage Range N to Vdc N to Vdc N to Vdc N to Vdc N to Vdc N to ~c 9. f the multimeter reading does not fall in the above range, adjust the left potentiometer as required to bring it within specifications (see Figure 2-1). Continue to hold the HGH/OFF/LOW switch in the LOW position while making the adjustment. 10. Hold the HGH/OFF/LOW switch in the HGH position and observe the multimeter reading. The following tabulation indicates the high voltage range that should appear for each type of Cab Signal Test Set: 6221, p. 2-2

13 CAB SGNAL TEST SET (SCALE EXAGGERATED FOR CLARTY) LOW LEVEL SGNAL ADJUSTMENT HGH LEVEL SGNAL ADJUSTMENT Figure 2-1. High/Low Sensitivity Adjustment Potentiometers Unit Part No. High Voltage Range N to Vdc N to Vdc N to Vdc N to Vdc N to Vdc N to vac 11. f the multimeter reading does not fall in the above range, adjust the right potentiometer as required to bring it within specifications (see Figure 2-1). Continue to hold the HGH/OFF/LOW switch in the HGH position while making the adjustment. 12. Remove test leads and close the access cap on the test set before putting the unit into service. 13. The above procedure must be repeated if the receiver coils are readjusted or replaced, or if the Cab Signal Test Set is replaced. 6221, p. 2-3/4

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15 SECTON OPERATON 3.1 CONTROLS AND NDCATORS Figure 3-1 shows the layout of the Cab Signal Test Set front panel. following tabulation summarizes the function of each device: The Device Name Type Function AUTO/HOLD SPOT Toggle Switch Determines whether test set will automatically cycle through each consecutive code rate (up, then back down), or stay on one particular code. AUTO: HOLD: automatic cycling stays at present code rate. HGH/OFF/LOW 4PDT Toggle Switch (spring return to center) Activates test set, determines relative level of simulated rail current and injects simulated carrier into cab signaling system. OFF: HGH: LOW: Power removed from test set, no generation of signals. 32 Vdc power applied, high current carrier signal put across receiver coil inputs to cab signal system. 32 Vdc power applied, low current carrier signal put across receiver coil inputs to cab signal system. CODE NDCATOR CALBRATE LED Test Jacks ndicates the particular code rate in progress. Flashes at that rate when the HGH/OFF/ LOW switch is in either the HGH or LOW position. Lights steadily when the full cycle is completed. Goes dark when switch is released back to the off position. Allow measurement of the simulated coil output current (with respect to input current). 6221, p. 3-1

16 SELECT: AUTO CYCLE THRU CODE RATES HOLD AT ONE CODE FLASHNG: CODE RATE WHEN RGHT HAND TOGGLE SWTCH S SET "HGH" OR "LOW" STEADY: FULL CYCLE COMPLETED DARK: HAND TOGGLE SWTCH "OFF" CAB SGNAL TEST SET m UNON SWTCH & SGNAL NC. HOLD CODE NDCATOR @ CALBRATE SELECT: 32 voe APPLED, HGH CURRENT CARRER APPLED TO RECEVER COLS TEST SET POWER OFF, NO SGNALS 32 voe APPLED, LOW CURRENT CARRER APPLED TO RECEVER COLS TEST JACKS: MEASURE COL TEST OUTPUT Figure 3-1. Cab Signal Test Set controls and ndicators 3.2 Operating Procedure 3.2.l Automatic Cycling NOTE Make certain the cab Signal Test Set is properly calibrated for the locomotive, before system tests are conducted. Refer to section 2.4 for procedure. l. Turn on cab signal equipment box (power now available to test set). 2. Set the AUTO/HOLD switch on the test set to the AUTO position. 3. Move the HGH/OFF /LOW switch to LOW position and keep it in that position. This action should cause the following: a. The CODE NDCATOR LED should begin flashing at the lowest code available with that particular test set. b. After five seconds, the next higher code rate should be shown on the LED, then the next higher and so on. c. The fastest code rate will be shown for 10 seconds, indicating that cycle has reached the fastest rate and is now starting downward again. 6221, p. 3-2

17 d. The next lower code rate will be shown for five seconds, followed by the next lower and so on. e. When the slowest code rate is completed, the CODE NDCATOR LED should change from the flashing state to the steady state. The LED will remain steady until the HGH/OFF/LOW switch is released. The aspect display should not light at any time while the HGH/OFF/LOW switch is held in the LOW position. f the display does show speed aspects, either the cab signal amplifier is too sensitive, or the test set is improperly calibrated. 4. Move the HGH/OFF/LOW switch to HGH position and keep it in that position. This action should cause the following: a. The CODE NDCATOR LED should begin flashing at the lowest cone available with that particular test set. b. After five seconds, the next higher code rate should be shown on the LED, then the next higher and so on. c. Each time the next highest code rate starts flashing (five second interval), the corresponding aspect display should light. d. The highest code rate will be shown for 10 seconds, indicating that cycle has reached the fastest rate and is now starting downward again. P.. When the highest code rate is reached, the corresponding aspect display should light. f. The next lower code rate will be shown for five seconds, followed by the next lower and so on. g. Each time the next lowest code rate starts flashing (five second interval), the corresponding aspect display should light and the audible alarm should sound (see step 5). h. When the slowest code rate is completed, the CODE NDCATOR LED should change from the flashing state to the steady state. The LED will remain steady until the HGH/OFF/LOW switch is released. 5. Bach time the audible alarm sounds, operate the ackwowlegde control to silence the alarm and continue the test cycle. 6. Optional test: When the cycle changes from the lowest code rate to continuous carrier (steady LED), do not acknowledge the audible alarm. The cab signal system should make the penalty brake application. The aspect display should not light at any time while codes are changing from lower to higher rates, and should always light when codes are changing from higher to lower rates. f not, the cab signaling system is faulty. 6221, p. 3-3

18 3.2.2 Manual cycling To manually cycle the Cab Signal Test Set, repeat the procedure given in section with the AUTO/HOLD switch starting in the AUTO position. However, when each new code begins flashing, move the AUTO/HOLD switch to the HOLD position. This prevents the test set from automtically moving to the next highest or lowest code rate, and allows extended troubleshooting of the cab signal system while that rate is in effect. To move to the next highest or lowest code rate, momentarily move the AUTO/HOLD to the AUTO position, and then back to HOLD. When using the HOLD mode, all responses from the test set LED and the aspect display should be the same as when using the AUTO mode. 6221, p. 3-4

19 4.1 CONTROL OF POWER AND TEST SGNALS SECTON V FUNCTONAL DESCRPTON (See Figure 4-1) Operating power (32 Vdc) is routed through pins E and B of the test set's 7-pin connector. Pins A and Fare connected across the pick-up coils. Simulated carrier and code signals generated by the test set are output on these pins. The HGH/OFF/LOW toggle switch is a momentary, return-to-center switch. The operator must manually hold the switch in either the HGH or LOW position to switch through operating power and produce test outputs. This feature is designed to prevent inadvertent operation of the set when the operator is absent. Pole 4 of the HGH/OFF/LOW switch routes the 32 Vdc input from connector pin E to Auto Code PCB 2 when the switch is placed in either the HGH or LOW position. When the switch is in the OFF position, power is aisconnected from the test set. Pole 3 routes power from connector pin E to pin F, which is connected to one end of the receiver coils. Pole 2 routes the test signal from Auto Code PCB 2 to connector pin A. Pole 1 actuates circuitry, on Auto Code PCB 2, that determines the level of test signal transmitted to the receiver coils. When the HGH/OFF/LOW switch is placed in the LOW position, the level of the test signal current provided to the receiver coils is slightly lower than the minimum rail current for which the equipment is calibrated. Conversely, when the switch is placed in the HGH position, the level of the test signal current is slightly higher than the maximum rail current for which the equipment is calibrated. For example, if the amplifier's sensitivity is set to operate between 1.3 to 1.6 amperes of rail current, the test will simulate a rail curr.ent of 1 ampere in the LOW position and 1.9 amperes in the HGH position. Testing is conducted by first checking the response of the cab signal equipment at the low current value, then at the high current value A correct response indicates that the equipment's sensitivity is between the minimum and maximum specified limits. When the HGH/OFF/LOW switch is moved off the center position, 32 Vdc is also switched to the input of the 3-terminal voltage regulator C on Auto Code PCB 2. The output of this regulator provides a regulated 15 Vdc to run C's on both test set PCB's. 4.2 SEQUENCNG OF CODE RATES rhe appropriate order to conduct code rate tests is with the lowest code frequency first, followed by the next high frequency, and so forth. When the fastest code rate is reached, the order is reversed until the slowest code rate is reached. This is done in the Cab Signal Test Set with re's that use internal binary codes to establish the direction and limits (upper and lower) 6221, p. 4-1.

20 HGH/LOW SWTCH CODE NDCATOR LED + 32V N V O' N N 'O.,::,. N "l'j f-'.q c:,., ().,::,.... (') n, O" tn f-' l.q ::, n,... r-3 (1) Cl) rr tn (1) rt le_v_el----m PCB # 1 LED DRVER P1 : HGH CURRENT SOURCE 14-~~~~~~~~~~~~~~~~~-+-~~~~~-----,. TEST SET : LOW CONNECTOR : A F COL P2. i OUTPUT r COL P3 :, 3 E + 32V P4 : TERMNAL + 1 SV REGULATOR B 'TUND ~ - a_.._ SELECTOR P1 75 P2 CODE P3 RE.ET P4 L - -, ~UT - t:, f-' n, Q,., n, 3 AUTO/HOLD SWTCH AUTO /Ho:o... ~ L MODE DETECTOR 0,... g :,;- DRECTON DETECTOR MAX. FLP-FLOP 1 UP/ ALLOW. DOWN UP SEL 1 COUNTER COUNT - 84 DETECTOR - r -CARRY PCB # SV OUT ~DOF 02 ~ CYCLE RESET 01 DETECTOR ' POWER +-L_CLEAR FLP-FLOP UP

21 of the output code rate. These circuits go through a complete cycle when the AUTO/HOLD switch is set in the AUTO position. When this switch is set in the HOLD position, the latest binary code (thus output code rate) is held indefinitely. The next code rate in the series can only be produced by moving the AUTO/HOLD switch to the AUTO position. This produces a bit that advances the counting devices to the next code rate in the series. The code controlling C's are initialized at power-up of the test set (HGH or LOW position of 3-position toggle switch) with a 500 millisecond start pulse generated on Auto Code PCB. At power-up, the Up/Down Binary Counter is reset to a binary zero state. The Direction Detector Flip-Flop is set to a logic one. This device determines the direction in which the Up/Down counter will count (up, when set to logic one). The End-of-Cycle Detector Flip-Flop is reset to a logic zero. With the AUTO/HOLD switch in the AUTO position, the Mode Detector circuitry enables the 5-Second Clock Oscillator. n turn, the oscillator advances the binary state of the Up/Down counter every 5 seconds. When a certain binary output is reached (representing the fastest code rate), the Maximum Allowable Up Count Detector toggles the Direction Detector Flip-Flop to the logic one. This reverses the Up/Down counter to the downward counting direction. n turn, the counter counts back down from the highest allowable binary number to a binary zero. Upon reached the binary zero, the counter generates a carry out signal. This signal holds the counter in its binary zero state and toggles the End-of-Cycle Detector Flip-Flop back to a logic zero. 4.3 CODE OSCLLATON SOURCE The actual oscillated code signal of the cab Signal Test Set is produced by the Code Oscillator circuit on Auto Code PCB 1. The frequency of this circuit is determined by the Code Selector circuit. The Code Selector is similar to a 6-pole single-throw switch. t switches any one of the six resistors on "pole" outputs Pl through P6 to the input of the Code Oscillator. A given pole is selected according to the binary code received from the Up/Down counter on Auto Code PCB 2. The Code Selector decodes the 3-bit binary number from the counter to decimal value at outputs Pl through PS. For example, if a binary 3 is received (1 1 O), the code selector connects the resistor on pole P3 to the input of the Code Oscillator. n turn, the Code Oscillator oscillates at the frequency determined by the magnitude of the resistance on line P SAMPLE OPERATON: UNT N After receiving the power up clear pulse, the 5 Second Clock Oscillator advances the Up/Down Counter from zero to one. The Code Selector decodes the received binary one and switches on the resistor on output P2 to the input of the Code Oscillator. n turn, the Code oscillator encodes the Carrier Oscillator at a 75 CPM code rate; this is shown by the CODE NDCATOR LED flashing 75 times per minute. 6221, p. 4-3

22 After five seconds has elapsed, the Clock Oscillator advances the Up/Down counter to a binary two. n response, the code Selector decodes the binary two and switches on the resistor on output P2 to the input of the Code Oscillator. n turn, the Code Oscillator encodes the Carrier Oscillator at a 120 CPM code rate; this is shown by the CODE NDCATOR LED flashing 120 times per minute. After another 5 seconds has elapsed, the 5 Second Clock Oscillator advances the Up/Down Counter to a binary three. n this particular unit (N }, the Maximum Allowable Up Count Detector is factory-set so that decoding of a binary three will cause an output that toggles the Direction Detector flip-flop. This changes the state flip-flop which, in turn, switches the Up/Down counter to count down on the next clock pulse received from the 5 Second Clock Oscillator. The Code Selector also responds to the binary 3 by switching on the line P3 resistor. n turn, the Code Oscillator cycles the carrier Oscillator at a 180 CPM code rate; this is shown by the CODE NDCATOR LED flashing 180 times per minute. After another five seconds, the Clock Oscillator decreases the Up/Down counter to a binary two. n response, the Code Selector decodes the binary two and switches on the resistor on output P2 to the input of the Code Oscillator. n turn, the Code Oscillator encodes the Carrier Oscillator at a 120 CPM code rate; this is shown by the CODE NDCATOR LED flashing 120 times per minute. After another five seconds has elasped, the same operation occurs for the 7~ CPM rate. After another five seconds has elapsed, the Clock Oscillator switches the Up Down counter back to a binary zero. The counter then generates a carry out signal to hold the counter at zero and toggle the End-of-Cycle Detector Flip-Flop. n turn, the output of the flip-flop changes state and locks off the Code Oscillator. Also, the CODE NDCATOR LED lights steadily. With the Code Oscillator locked off, the carrier Oscillator is free to generate uncoded continuous carrier, which is shown by the steady pattern of the LED 6221, p. 4-4

23 SECTON V FELD MANTENANCE 5.1 GENERAL PROCEDURES US&S recommends that the Cab Signal Test Set be returned to US&S for repair or replacement when it is suspected of being faulty. Repairs can also be performed by the customer using the procedures in section V. However, tests should first be conducted on the cab signaling equipment to make certain that it is not the source of the problem. For example, the equipment may not be supplying the 32 Vdc (.!:_ 0.2 Vdc) necessary to power the test set. There may also be a defect in the cabling that interrupts the power feed. This can be checked by (1) detaching the connector at the test set, (2) connecting a multimeter to the female connector c + to pin E, - to pin B) and checking for the required 32 Vdc reading with the cab signal equipment box turned on. A defect in the cabling could also prevent the test set from delivered the coded carrier signal to the cab signal equipment. The cab Signal Test Set may also appear to be faulty if the sensitivity setting is out of calibration, or if the locomotive receiver coils were replaced or readjusted. Perform the procedure in section 2.4 before replacing the unit. f the Cab Signal Test Set is malfunctioning, the CODE NDCATOR LED will not light, or will show the wrong patterns (refer to section 3.2). However, the LED and/or its driver circuit may be faulty, while the test set continues to provide the correct test signals. The entire set should be replaced in this instance. Replace the test set also if either toggle switch is damaged. This is most important in the case of the HGH/LOW/OFF switch. f the switch continues to generate test signals after the operator removes his grip, the cab signaling system will receive erroneous indications. After replacing the test set, make certain to perform the calibration procedure given in section PERODC NSPECTON AND CALBRATON The cab Signal Test Set should be periodically inspected and checked for proper cablibration at once every 12 months (FRA Rule ), and each time receiver coils are replaced. For inspection, check that unit mounting screws, front cover screws, cable connector, dummy connector cap and toggle mounting nuts are tight. Also check that both toggle switches are moving properly: two positions for AUTO/HOLD, 3-position return-to-center for HGH/OFF/LOW. Use the procedure in section 2.4 for periodic calibration checks of the test set. 6221, p. 5-1/2

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25 SECTON V SHOP MANTENANCE 6.1 GENERAL Testing of the Cab Signal Test set internal circuitry should only be performed by properly trained and equipped personnel. Procedures in this section include testing of the set as a complete unit, in order to localize the problem in a functional sense, and testing of components and circuits on the two PCB's. Appendix A lists all replaceable parts in the set. 6.2 UNT FUNCTONAL TEST 6.2.l Required Test Equipment Device Power Supply (Qty= 1) Oscilloscope (Qty= 1) Resistor (Qty= 1) Cable Plug Connector (Qty= 1) Cable Clamp (Qty= 1) Cable Rubber Bushing: Specifications +32 Vdc@.05 amps (Harrison model or equivalen~) Tektronix Model 561A or equivalent. lok Ohm, 1%, 1/4 W, or equivalent decade'box US&S ij US&S J US&S J Test Set-Up 1. Assemble the test cable connector and wiring. Figure 2-1 provides cable assembly information. 2. Connect the test equipment as shown in Figure 6-1 but leave all equipment turned off. 3. Turn on power supply and adjust to 32 Vdc, Vdc. 4. Turn on oscilloscope Test Procedure Conunents Steps 1 through 3 of the procedure (section 6.2.4) verify whether the test set is producing the uncoded continuous carrier signal. Step 4 is a preliminary check of the set's complete coding cycle. Steps 5 through 7 check the transistion of the set from the initial, continuous carrier to the slowest code rate in both the LOW and HGH modes. Steps 8 through 11 are a continuation of steps 5 through 7, going up and back through all remaining codes. The signal periods of the different units are listed in tabular form. 6221, p. 6-1

26 POWER SUPPLY + E 8 F A STRAGHT CONNECTOR PLUG 10K OHMS -1% OR R. BOX GND 0 OSCLLOSCOPE PROBE Figure 6-1. Set-Up for General Test of Unit Procedu r,? Operation Verification 1. Place the AUTO/HOLD switch in the HOLD position Hold the HGH/OFF/LOW switch in 2. the LOW position and observe both the CODE NDCATOR LED and the oscilloscope display. J. Repeat step 2 with the HGH/OFF 3. LOW switch in the HGH position. The CODE NDCATOR LED should light steadily and the scope should show the waveform in Figure 6-2. f this waveform does not appear, discontinue procedure and go to section 6.3. The CODE NDCATOR LED should light steadily and the scope should show the waveform in Figure 6-2. f this waveform does not appear, discontinue procedure and go to section , p. 6-2

27 PEROD -.J l PEAK-TO-PEAK 1 Unit Part No. HGH/LOW/OFF Wave P-P Peri on N switch Pos. Amplitude (V) (msec.) LOW 0.6 to HGH 1.0 to l LOW 0.5 to 1.0 q HGH 1.0 to lo LOW 0.6 to 1.0 l HGH 1.0 to LOW 0.5 to HGH 1.0 to LOW 0.6 to HGH 1.0 to LOW 0.5 to HGH 1.0 to Figure 6-2. Unit Test Waveform fl 6221, p. 6-3

28 Operation Verification 4. Place the AUTO/HOLD switch in 4. the AUTO position and hold the HGH/OFF/LOW switch in either position. 5. Hold the HGH/LOW switch in the S. HGH position until the CODE NDCATOR LED begins to flash, then immediately throw the AUTO/ HOLD switch to the HOLD position. The test set should automatically sequence up and down through the codes available with the particular unit no., as shown on the CODE NDCATOR LED (refer to section 3.2). The CODE NDCATOR LED should light steadily 2 to 3 seconds before flashing. The scope. should display the waveform shown in Figure Move the AUTO/HOLD switch back to the AUTO position. 7. Hold the HGH/LOW switch in the ~ LOW position until the CODE NDCATOR LED begins to flash, then immediately throw the AUTO/ HOLD switch to the HOLD position. The CODE NDCATOR LED should light steadily 2 to 3 seconds before flashing. The scope should display the waveform shown in Figure Move the AUTO/HOLD switch back ~. to the AUTO position. 9. Hold the HGH/OFF/LOW switch in ~. the HGH position. The CODE NDCATOR LED should light steadily 2 to 3 seconds after the HGH/OFF/LOW switch is moved to the HGH position. Then the LED should flash for about 4-6 seconds. Next, the flash rate of the LED should increase, repeat or decrease, depending on the type of unit. Go to step 10 as soon as this happens. 10. Move the AUTO/HOLD switch to the HOLD position as soon as the flash rate changes. Continue to hold the HGH/OFF/LOW switch in the HGH position. lo. Refer to Table 6-1 for the proper coding periods of each unit, as shown on the scope display. 11. Repeat steps 8 through 10 until 11. the CODE NDCATOR LED lights steadily (indicating uncoded carrier.) When the fastest flash {code) rate is reached, that rate should repeat once. Then the flash rates should decrease after each 4-6 interval. After the slowest code rate is reached, the LED should be steady. 6221, p. 6-4

29 PEAK TO PEAK J_ PEROD Unit Part No. HGH/LOW/OFF N Switch Pos. Wave P-P Amplitude {V) Period {msec.) LOW HGH LOW HGH LOW HGH LOW HGH LOW HGH LOW HGH 0.6 to to to to to to to to to to to to Figure 6-3. Unit Test Waveform t2 6221, p. 6-5

30 Table 6-1. Coding Period Test Measurements Unit Part Number AUTO/HOLD N Switch Pos. status Coding* Uncoded** -1501, AUTO 75 to 120 CPM.. HOLD 120 CPM 460 to 512 n " AUTO 120 to 180 CPM " HOLD 180 CPM 300 to 340 n n AUTO 180 to 120 CPM " " HOLD 120 CPM 460 to " AUTO 120 to 75 CPM " HOLD 75 CPM 790 to AUTO 75 CPM to steady to AUTO 75 CPM to steady 9.5 to O , AUTO 75 to 120 CPM " HOLD 120 CPM 460 to 512 " AUTO 120 to 180 CPM " HOLD 180 CPM 300 to 340 n.. AUTO 180 to 270 CPM.... HOLD 270 CPM 210 to AUTO 270 to 410 CPM n HOLD 410 CPM 135 to 150 " " AUTO 410 to 270 CPM " " HOLD 270 CPM 210 to 235 ".. AUTO 270 to 180 CPM " HOLD 180 CPM 300 to AUTO 180 to 120 CPM HOLD 120 CPM 460 to 512 " AUTO 120 to 75 CPM.. " HOLD 75 CPM 790 to AUTO 75 CPM to steady 15.8 to AUTO 75 CPM to steady 9.5 to 10.5 * Period of coding, as observed on scope. **Period of continous square wave (Continued on following page) 6221, p. 6-6

31 Table 6-1. Coding Period Test Measurements (Cont'd} Unit Part Number AUTO/HOLD N Switch Pos. Status Coding* Uncoded** -1505, AUTO 50 to 75 CPM.... HOLD 75 CPM 790 to AUTO 75 to 120 CPM HOLD 120 CPM 460 to 512 ".. " AUTO 120 to 180 CPM ff HOLD 180 CPM 300 to 340 ".. AUTO 180 to 270 CPM.. HOLD 270 CPM 210 to 235 n AUTO 270 to 410 CPM " HOLD 410 CPM 135 to 150 n.. AUTO 410 to 270 CPM n.. HOLD 270 CPM 210 to 235 n AUTO 270 to 180 CPM n.. HOLD 180 CPM 300 to 340 " n AUTO 180 to 120 CPM ff HOLD 120 CPM 460 to 512 n AUTO 120 to 75 CPM " HOLD 75 CPM 790 to 875 " " AUTO 75 to 50 CPM HOLD 50 CPM 1200 to AUTO 50 CPM to steady 15.8 to AUTO 50 CPM to steady 9.5 to 10.5 * Period of coding, as observed on scope. **Period of continous square wave 6221, p. 6-7

32 6.3 PCB TROUBLESHOOTNG 6.3.l General Both of the Cab Signal Test Set's PCB's (Auto Code PCB land Auto Code PCB 2) are tested in a single, comprehensive procedure. There are several versions of these boards, which are used in the different versions of the test set. Refer to Appendix A. section A.l for PCB/unit part number cross referenc~s Detailed Circuit Descriptions l Auto Code PCB l (N , -8302, -8303) (See Figure 6-4) Rl5, c2 and the gate of the C5 inverter at pins 1, 2 and 3 make up the power-up clear circuitry for the board. When power is applied to the PCB, the output of C5/pin 3 goes high. When C2 changes to approximately 30% of the supply voltage, res switches low. The momentary pulse generated by res initializes Up/Down Counter C2, which is reset to a binary o. The res pulse also initializes Flip-Flop C4/pin 2, which is reset to a logic 1. (The state of C4 determines determines the counting direction of C2: f C4 sends a logic 1 to C2/pin 10, C2 counts up. Conversely, if C4 sends a logic Oto C2/pin 10, C2 counts down.) The C5 pulse also resets flip-flop C5/pin 13 output to a logic O. When the power-up clear pulse is produced, C2 is advanced on each low-to-high transition of Clock Oscillator!Cl/pin 8, until the preprogrammed number is reached. The oscillation frequency of the!cl/pin 8 output is determined by R7, RS and Cl. rel/pin 8 oscillates at 0.2 Hz or once every 5 seconds. Cross coupled gates of res are used to gate Cl on or off. rel is held off when the output of gate C5/pin 10 is high. Cl is free to oscillate when the output of CS/pin 10 is low. The output of C5/pin 10 is high when turret tl is low and turret #2 is high. Conversely, the output of!cs/pin 10 is low when turret fl is hlgh and turret t2 is low. Four-bit magnitude comparator C3 compares the 4-bit binary number received from C2 with a preprogrammed 4-bit binary number. C3 is factory-programmed with permanent jumper wires between the B input (BO thru 83) and ground or +15 Vdc. The B inputs of C3 are programmed for a binary 3, 5 or 6, as determined by the PCB part number. For example, a binary 3 programmed on the B inputs causes the following operations: After the power-up clear pulse is produced, Cl advances C2 on each low or high transition every 5 seconds. C2 counts in binary order from Oto a binary 3. When binary 3 is reached, the binary 3 programmed in on the C3 B inputs is compared with the binary 3 received on the A inputs. The output of C3/pin 3 then decodes, toggling flip-flop C4. The output state of C4/pin 2 change, signaling C2 to count down on the next clock pulse received from!cl. After 5 seconds has elapsed,!cl clocks C2 back to a binary 2. After another 5 seconds, it clocks C2 back to a binary 1. After another 5 seconds, it clocks C2 back to a binary o. Upon reaching o, C2 generates a carry out signal at pin 7. This signal holds C2 at binary O and toggles C4/pin 11. The output of C4/pin 13 changes state from low to high. This indicates that the PCB has made one complete coding cycle. 6221, p. 6-8

33 +15 VOL TS E::---- ~ ~ 111 4' BJ A: B N Li &- B A B 2 N 9 B A<B O S L,, "~... :::r. +l,,~j 1C3 N 0 U J.. ~ 68K!Cl RS 4541 ~ ~ _._(." y - 1..JA, A:e J.01 R a 10A.. A<B 4 ~-,., v<:.c:: t,a SkL R_.,,i,,,,j,, JCS R4 AUTO ~ --1r~ 4 ~'--- "0t Rt "'201; RJt ~j [s j 4 r;i \ \/ v ~ ~ a, ~ R2 <SOK RS< OOK.1 CL TEST PONT R5 <3--f :c-1,,. ~ ~~POWER UP CLEAR RE ~ ~-r::----. ENERGY CL ~ STEADY Q L_L-J 8 7 AUTOMATC CODE TEST SEE PCB l'w + v~ Figure 6-4. Auto Code PCB 1 Schematic Diagram 6221, p. 6-9/10

34 Auto Code PCB 2 (N , -8402, -8493, -8404, -8405, -8406) (See Figure 6-5) Test set operating power is received at C4, a 3-terminal regulator. provides a regulated +15 Vdc output to power!c's 1, 2 and 3. C4 The frequency (code rate) of Oscillator C2 is determined by!cl.!cl is an 8-channel, digital-controlled multiplexer. t selects one of eight poles (PO thru P7) and switches the selected pole, and associated resistors, to the input of rc2. A pole is selected according to a 3-bit binary number received on turret lugs 8, 9 and 10 from Auto Code PCB 1.!Cl receives this number on its AB c inputs, and converts it to decimal form on its p outputs. For example, a binary 3 (1 1 0) causes!cl to switch through Rl7 and R32 on output P3, to the input of rc2. n turn, C2 oscillates at a frequency determined by the magnitude of the Rl7 and R32 resistance connected to P3. The output of C2/pin 8 switches on and off Oscillator C3/pin 6, and LED driver transistor Q2 at the corresponding code rate. The oscillation frequency of C3 is determined by R22, R38 and C2. rc3 oscillates at 100 Hz or 60 Hz, depending on the PCB part number and corresponding application. The output of C3/pin 8 drives current source Ql. Ql generates one of two regulated levels of coded carrier current and provides this current at turret lug t13. High-level carrier current is obtained by connecting turrets 3 and 2 and adjusting potentiometer R7. Low-level carrier current is obtained by connecting turrets 3 and 4 and adjusting potentiometer R8. The output at turret tl3 generates uncoded continuous carrier by applying +15 Vdc to the steady energy input at turret tll. When +15 Vdc is applied to turret tll, C2 is shut off. n turn, LED driver Q2 is turned off. With C2 held off, the C3 is free to generate uncoded carrier to current source Ql Required Test Equipment This test procedure uses the same test equipment as the general unit test, as listed in section 6.2.l. n addition, the following instruments are required: Device Multimeter (Qty= 1) Counter (Qty= 1) Specifications Fluke 8000A or equivalent Atec 5A35 or equivalent Test Set-Up and Physical Check 1. Loosen the four screws which secure the front cover of the test set and carefully remove the cover (screws are permanently attached to cover.) 2. ~lamp the cover on a stand that permits the front switches to be easily operated. Make certain that the terminals on the toggle switch and test jacks do not touch a conductive material. 3. Check all internal wiring for loose or broken connectia~s. 6221, p ;. ~ :~.- ~ ~. i.

35 4. Remove the four screws that hold the 7-pin connector and partially extract the connector from the housing. Do not unsolder any of the wiring on this connector. 5. Remove the four screws holding down the PCB's. 6. carefully lift the top PCB out and rest it on a dielectric material with the component side up. 7. Check for loose, missing or damaged components on both PCB's. 8. connect the test equipment in the same arrangement as the unit test (see Figure 6-1), but leave all equipment turned off. 9. Turn on power supply and adjust to 32 Vdc, Vdc. 10. Turn on oscilloscope Test Procedure comments steps 1 through 3 verify that C4 of Auto Code PCB 2 receives 32 Vdc power when the HGH/OFF/LOW switch is moved off the center position. Step 4 checks the 15 Vdc output of the voltage regulator on Auto Code PCB 2. f step 4 shows that a faulty C is loading down the regulator, steps 5 through 6 are run to determine which PCB contains this C. Steps 8 through 22 check selected components on Auto Code PCB t2. Steps 23 through 39 check selected components on PCB tl. Steps 40 to 47 check the operation of Up/Down counter C2, comparator C3 and Flip-Flop C4 by exercising all available codes. Part of the procedure is provided in tabular form. Table 6-2 shows the nominal outputs of C2 when the code rates of the particular unit are being increased. Table 6-3 shows the nominal outputs of C2 when the code rates of the particular unit are being decreased. 6221, P 6-12

36 'lutput t ()1( R6 +SV a-- -,,LEVC:L 3 4JLOW C4 - ",CJ18L ~5ACG 1 2 "D-L ~: r~ +SV... ~ R7J 20olC.!:.f R29.RS -SOOK R Oo~ Cli 19 0,z 110 R2 ZOK R"? 2()1( R9 51()1( ~to s&ok 16,voo 11 A c 8!Cl ~,' PO 13 Pl 114 P2 115 P3 1' 2 Rl4 ~ Rl5 V' TBD Rl6 t61i RT t61i Rl8 t61i Rl9 t61i R20 t61i R21 V' TBO R23 V' TBO R30 V' 52.JK R31 3~ R32 ~ R33.~( R34 9~ R35. 5~ R24 ","' R39 ; R~22 R38 1 b CTC 1 R37 w ~" r--2--ar "7 l ~ 6~ R25 20K C j <? ~ vool'4 J A,12 ~ 11 MO. [ (.. a,11\ , 01 8 CODE TEST '-----~ 51K _J :~~:~~ 111 P.4 2()1( i'~ t t'z ('>.. CODE y NDCATOR! J, ~26 '. 1.SK -~,, CLEAR@::> V' l 2()1( urow.r1c COOE Tt:,T SET PCB 2 1Rl3 51()1( Figure 6-5. Auto Code PCB 2 Schematic Diagram 6221, p. 6-13/14

37 6.3.6 Procedure Ope rat ion Verification 1. Connect multimeter + lead 1. to turret lug 16 on PCB t 2, and ground lead to power supply ground. See Figure 6-6 for turret lug location and unit chassis wiring. 2. Place the HGH/OFF/LOW switch 2. in the HGH position. 3. Place the HGH/OFF/LOW switch 3. in the LOW position. 4. Reconnect multimeter high input 4. terminal to turret 15 on PCB 12, and repeat steps 2 and Check the current draw on the 5. multimeter. 6. Unsolder wire at turret 15 and 6. recheck voltage and current draw on that turret. Multimeter should show 32 Vdc Vdc. Check wiring from turret-16 to HGH/OFF/LOW switch, and from switch to connector. same as step 2. Multimeter should show to Vdc for both switch positions. f the reading is O Vdc, replace C4 on PCB 2. f the reading is out of tolerance continue with step 5. The current draw should not exceed 20 millamps. f it does (faulty C loading down C4 on PCB 2), continue with step 6, otherwise replace C4. f voltage is still out of tolerance and current draw still exceeds 20 millamps, there is probably a faulty C on PCB 2. Otherwise, faulty C is probably on PCB Resolder wire to turret Place the AUTO/HOLD switch in 8. the HOLD position. 9. Hold the HGH/OFF/LOW switch in 9. LOW position, and observe both the scope display and the CODE NDCATOR LED. Do the same with the switch in the HGH position. The CODE NDCATOR LED should light steadily and the scope should show the waveform in Figure 6-2. f the LED does not light, either the LED and/or Q2 on PCB 2 is faulty. f scope does not show a square wave, continue with step , p

38 Operation Verification 10. Reconnect scope as follows: probe to turret f4 on PCB f2. Ground to - terminal of power supply. 11. Hold the HGH/OFF/LOW switch in 11. f the scope shows waveform fl the LOW position. of Figure 6-7, Ql of PCB 2 may be faulty. f no waveform appears, continue with step Reconnect scope probe to end of R6 which is connected to C3/ pin 8 (PCB 2). 13. Hold the HGH/OFF/LOW switch in either the HGH or LOW position f the scope shows waveform fl of Figure 6-7, Ql of PCB 2 may be faulty. f no waveform appears, continue with step Reconnect scope probe to turret on PCB f Repeat step f scope shows Oto 25 Vdc, C3 of PCB 2 may be faulty. f scope shows 5 to 15 Vdc, C2 of PCB 2 may be faulty. 16. Move the AUTO/HOLD switch to the 16. AUTO position. 17. Hold the HGH/OFF/LOW switch in 17. the HGH position and move the AUTO/HOLD switch to the AUTO position as soon as a square wave appears on the scope. Use steps 8 through 11 of section to check the remaining code rates. About 2 to 3 seconds after the HGH/OFF/LOW switch is put in the HGH position, the scope shoulrl show a square wave with a P-P amplitude of 15 Vdc, + 1 Vdc. The period of the square wave should be the same as those listed in Figure 2-3. f the scope does not show a square wave, C! and C2 of PCB 2 may be faulty. 18. Reconnect scope probe to turret 18. #10 on PCB # , p. 6-17

39 Operation Verification 19. Move the AUTO/HOLD switch to the 19. AUTO position. 20. Hold the HGH/OFF/LOW switch in the HGH position. 21. Reconnect scope to end of R36 that is connected to C2/pin 3 on PCB f Hold the HGH/OFF/LOW switch in the HGH position and move the AUTO/HOLD switch to the AUTO position as soon as a square wave appears on the scope. 20. About 2 to 3 seconds after the HGH/OFF/LOW switch is put in the HGH position, the scope shoulo show a change from ground (0 to 1.0 Vdc) to 15 Vdc, Vdc. f the voltage does not-switch to 15 Vdc (possible fault on PCB fl), go to step 23. f the scope does show the proper voltage, continue with step About 2 to 3 seconds after the HGH/OFF/LOW switch is put in the HGH position, the scope may show a square wave with a P-P amplitude of 15 Vdc, + 1 Vdc. The period of the square wave would be as follows: Unit No. Period to 895 msec to 895 msec to 895 msec to 895 msec to 1350 msec to 1350 msec. f the scope does show the square wave, C2 on PCB 2 may be faulty. f no square wave is produced, then Cl on PCB 2 may be faulty. 23. Reconnect multimeter + lead to turret t9 on PCB fl and - lead to the power supply ground. 24. Hold the HGH/OFF/LCM switch in 24. Multimeter should show 15 Vdc either position..:!:. 1.0 Vdc. 6221, p r, ~- -