VA-100NC VIDEO DISTRIBUTION AMPLIFIER

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1 II R T Electronics Pty. Ltd. A.C.N Hotham Parade, ARTARMON. N.S.W. 064 Australia National: Phone: ( Fax: (0) International: VA-00NC VIDEO DISTRIBUTION AMPLIFIER Telecom Serial 347 Item DESIGNED AND MANUFACTURED IN AUSTRALIA

2 VA-00NC VIDEO DISTRIBUTION AMPLIFIER INSTRUCTION BOOK Serial 347 Item 55 Section Contents Page. General Description 3.. Accessories Available Technical Specifications Circuit Description Installation Setting up Procedure Maintenance Table of Voltages Circuit Diagrams 0. Parts Lists WARNING OPERATION OF ELECTRONIC EQUIPMENT INVOLVES THE USE OF VOLTAGES AND CURRENTS WHICH MAY BE DANGEROUS TO HUMAN LIFE. OPERATING PERSONNEL SHOULD OBSERVE ALL SAFETY REGULATIONS. DO NOT CHANGE COMPONENTS OR MAKE ADJUSTMENTS INSIDE THE EQUIPMENT WITH POWER ON UNLESS PROPER PRECAUTIONS ARE OBSERVED. NOTE THAT UNDER CERTAIN CONDITIONS DANGEROUS POTENTIALS MAY EXIST IN SOME CIRCUITS EVEN THOUGH POWER CONTROLS ARE IN THE OFF POSITION

3 GENERAL DESCRIPTION The VA-00NC is a B.C. powered Video Distribution Amplifier of modular construction having facilities for cable equalization, longitudinal hum reduction and clamping. The input is designed to provide a bridging loop impedance over the video bandwidth with respect to 75 ohm. Six 75 ohm D.C. coupled outputs are provided. The input and output grounds are separated to allow for rejection of longitudinally developed hum. Cable equalization is provided for up to 300 metres of 75 ohm video cable. Front panel controls allow the video gain to be varied by a minimum of +/- 3dB, and the cable equalisation to be independently set to compensate for the appropriate length of cable. Internal pre-set controls allow adjustment of the amplifier high frequency response, optimization of the longitudinal hum rejection, and output stage D.C. component. The VA-00NC is operated from negative 48V D.C. Equipment provided:- VA-00NC Video Distribution Amplifier Slide Tray RB-N Rear Assembly 80995

4 ACCESSORIES AVAILABLE F-00D Module Mounting Frame :- Provides mounting for up to 0 VA-00NC amplifiers side by side in 34mm of standard Rack space. (3 Rack Units) TME-A RB-N Module Extender: Enables a module to be operated in position and provide access to all circuit boards, transistors and internal adjustments. Rear Assembly: An additional rear assembly may be purchased to permit bench testing and servicing of the amplifier without disturbing the rear assemblies supplied with the amplifiers

5 SPECIFICATIONS Input power 47 to 53V DC (+ve 5mA in accordance with Telecom Australia Spec 00. INPUT CHARACTERISTICS Input impedance Input connector Longitudinal hum rejection Maximum level Bridging loop input with return loss >40dB to 6MHZ.6/5.6 >40dB >V p-p ( OdB gain) TRANSFER CHARACTERISTICS Overall gain High Frequency response Differential gain Differential phase Noise Operating temperature range Cable equalisation >+ 3dB + O.ldB to 0MHz + 0.dB to 0MHz bandwidth exceeds 30MHz <0.5% at 4.43MHz o <0.5 at 4.43MHz >70dB 0kHz to 5MHz unified weighted o o 0 C - 55 C Front panel control equalising up to 300m of 75ohm cable OUTPUT CHARACTERISTICS Number Impedance Return loss Overload DC on output Output Connector 6, dc coupled 75ohms, source terminated >40dB to 6 MHz 3.0V p-p on 4.43MHz sine wave.5v p-p on pulse adjustable to 0V.6/5.6 FRONT PANEL FACILITIES * Gain adjustment * Cable equaliser adjustment * Clamp on/off indication * Fuse * Power on LED 80995

6 CIRCUIT DESCRIPTION Refer to Drawing no The block diagram shows that the VA-00NC comprises :- (a) An input stage:- which has a high input impedance to bridge the video source, an equaliser for correction of input coaxial cable losses, and a 75 ohm source terminated output. (b) A "plug-in area: - for accessories not Link bypasses this feature. yet defined. (c) An output stage:- with 6 75 ohm source terminated outputs. This stage may have its black level clamped to 0V by placing LK in the 'On' position. (d) Clamp logic:- a sync separator and back porch sample pulse generator is fed from the output of the Input stage. Video from the output of the Output stage is firstly low pass filtered (to remove chroma and noise) and then applied to a sample switch. This switch, under control of the sample pulse stores in a sample and hold capacitor the back porch error signal. If LK is in the 'On' position this error is applied to the inverting input of the Output stage to correct the offset. (e) Power Supply:- the -48V DC input voltage is fed via an on board fuse to a DC-DC converter. The output of the converter is + and - 5V. These supplies are further regulated to + and - V by 3 terminal regulators. The LED on the front panel is wired in series with a zener diode between + and - Volts. The zener is to ensure that the LED extinguishes if any one of the regulators fails. Video Clamp LK On enables back porch clamp Off disables back porch clamp Accessories LK Inserted by-passes accessories Removed accessories can be inserted

7 INSTALLATION The VA-00NC is supplied with a slide tray, rear assembly and associated hardware, for mounting in an F-00D frame. Slide Tray The slide tray is a shallow tray which supports the amplifier in the frame. It is mounted on the front and rear cross members of the frame and is fixed in place with steel clips (speed nut type) provided. Rear Assembly The rear assembly is mounted on the rear of the frame with the screws provided. Care should be taken not to over tighten these screws, as excessive force will damage the thread in the mounting frame. Signal Connections Signal connections are made via coaxial connectors mounted on the rear assembly. The input loop, if not used should be terminated in 75 ohm as should any unused outputs of the amplifier. SETTING UP PROCEDURE The amplifier should be set up in the position in which it is intended to be operated. Adjustments can then be made using the intended lengths of cable and with all outputs terminated as they would be in service. The cable equalizing should be set to its minimum and the gain control adjusted to give the required low frequency gain. Using a suitable test signal, such as pulse and bar, multiburst or sweep, the cable equalization can be advanced to compensate for input cable losses. It should be noted that the equalizers are factory set to match Belden type ohm cable. Whilst for short runs this equalizer will be satisfactory for most 75 ohm solid dielectric cables, for longer runs of some cables the equalizer may have to be reset (a factory adjustment) or replaced with a specially designed module. If backporch clamping is required LK should be put in the 'Clamp On position and the Clamp On LED on the front panel

8 should illuminate. If clamping is not required LK should be in the 'Clamp Off position

9 MAINTENANCE Once having been adjusted the Video Distribution Amplifier will need little attention. It is wise however to occasionally check the adjustments as described earlier. This will also be necessary after a component has been replaced. Most faults can be readily traced by checking the B.C. voltages at various points in the circuit. The table of voltages given in this book can be used as a guide but deviations sometimes in the vicinity of +/- volt can be expected in some units. The voltages should be checked starting from the input as the B.C. conditions of the whole amplifier are set in the first stage, thus a fault early in the circuit will cause errors at the output. Internal Adjustments The following adjustable resistors and capacitors are factory set and should not be adjusted unless a component has been changed. They are not 'operational controls. Before adjusting any of these controls allow time for the VA-600 to reach temperature stability. RV3 Hum:- Adjusted to best cancel hum on the input cable. must not be in operation during this adjustment. The clamp RV BC Offset:- With no input signal applied RV is used to set the junction of R R4 to zero volts. C Freq Resp:- Used to set the frequency response of the input stage to maximal flatness when observed at the junction of R R4. RV4 BC Offset:- With no input signal and with LK installed and after adjustment of RV, RV4 can be adjusted so that the junction of R9 R30 is zero volts. C5 Freq Resp:- Used to set the frequency response of the output stage. Maladjustment of this capacitor can cause instability in the amplifier under extreme conditions

10 TABLE OF VOLTAGES Q Emitter Base Collector -0.7 ~ ~ ~ ~ ~0 U ~0 0 ~ All voltages measured with a high input impedance multimeter under conditions of unity gain. All voltages are measured with respect to earth. Supply voltage is -50.0V B.C. Test signal is IV P-P composite Stair Step and the Clamp is off

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12 IV P -P TERMINATED 0-SV P-P IV P-P TERMINATED OPTIONAL PLUG-IN BOARD 6 OUTPUTS f-j! I i I I SAMPLE SWITCH TliV + I5V + I - *6V INPUT DC -DC CONVERTER ~* -ISV - ^ ^ POWER DftAWN 3&AA Q*TE IRT IXI SCALC VA-lOO NC BLOCK DIACKAM 8OZ9S5 SHEET. or 3.

13 /T PART OF VA OONC CIRCUIT / \G CHANGED COMPONENTS I FOR SPECIFICATION 7 H RV, J SOR FT EQ* SPECIFICATION 5S7 R6 CUD f ' 5R C6 I 8PT? R63 p cm! T 43R aci7 ciaj R64 J f K C9 CO_ "* 6Op SOpT" ^"" 6Op 8p~T ' R65 l==l K C C 60p p i 9 g COPYRIGHT DO NOT COPY NOR DISCLOSE TO ANY THIRD PARTY WITHOUT WRITTEN CONSENT DRAWN K.N. CHECKED ENO. APP. CONTRACT No. SIZE: SCALE DLEU TITLE: VA IOONC CABLE COMPENSATION TO SPECIFICATION 7 SPECIFICATION 557 DRAWING No. 8O9B5 SHEET 3 OF 3 IRT Electronics Pty. Ltd. ARTARMON NSW AUSTRALIA O84-

14 ORIGINAL ISSUE DATE IT II ll Is a H CD O o o o o o o o o o o o o 060 (P * in o

15 I.R-T- ELECTRONICS»TY. LTD.! Part No. PC80994 SFR6T-R8 SFR6T-4R7 SFR6T-R SFR6T-7R SFR6T-33R SFR6T-68R SFR6T-75R SFR6T-00R SFR6T-0R SFR6T-50R SFR6T-0R SFR6T-70R SFR6T-360R SFR6T-470R SFR6T-80R SFR6T-K SFR6T-K SFR6T-K5 SFR6T-3K9 SFR6T-4K7 SFR6T-5K6 SFR6T-0K SFR6T-K SFR6T-K SFR6T-33K SFR6T-47K SFR6T-8K Replacement Parts List VIDEO DISTRIBUTION AMPLIFIER ASSEMBLY VA-00NC Page of 4 Description. PCS VA-00NC RESISTOR METAL FILM. 5W 5% RESISTOR METAL FILM. 5'W 5% Qty i Get Ref. R8 R9,30 R5, 6,,3, 9, 0, 6 RIO R7 R60 R4,7 R6,67 R74 R8 R3,4 R,46,7 R63 R5,6,5,57 R7,,7 R8/4-43,69 R9,,64, 70 R3,4,75 R,68 R48,5,54,65 Rl,49,5 R6 R56 R50 R53 R55 R58 Sup! 0: /0/9

16 I.R.T. ELECTRONICS I»TY. LTD - Part No. SFR6T-00K SFR6T-70K RMF55-3M3 RMF5-75R ASW--6R8 WAG04S5U 339H-0 339H-0 CC4P7 CC8P CC47P CC00P CC0P CC50P CC390P CC0N CCN CC47N CC00N CP0N/63V TT/35 TT/6 RT47/63 RB0/6 TZ03070E TZ03P600E Replacement Parts List VIDEO DISTRIBUTION AMPLIFIER VA-00NC Page of 4 Description. RESISTOR METAL FILM.5W % RESISTOR WIRE WOUND W RESISTOR VARIABLE 5 OR RESISTOR VARIABLE 00R RESISTOR VARIABLE IK CAPACITOR CERAMIC 4. 7pF CAPACITOR CERAMIC 8. pf CAPACITOR CERAMIC 47pF CAPACITOR CERAMIC loopf CAPACITOR CERAMIC 0pF CAPACITOR CERAMIC 50pF CAPACITOR CERAMIC 390pF CAPACITOR CERAMIC 0nF CAPACITOR CERAMIC nf CAPACITOR CERAMIC 47nF CAPACITOR CERAMIC loonf CAPACITOR POLY 0NF 63V CAPACITOR TAG TANT luf/35v CAPACITOR TAG TANT uf/6v CAPACITOR ELECTRO 47uF/63V CAPACITOR ELECTRO 0uF/6V CAPACITOR VARIABLE -7pF CAPACITOR VARIABLE 0-60pF (Z5U) (BLUE) (BROWN) Qty R44 R47 R45 R3-36 R73 RV,5 RV3 RV,4 Get Ref. C3 C4 C6 C9,, C7,4,5,0 C6,8 C8 CIO, 3,3, 33, 34 C4 C ClOO-03,06,07,0 C35,36 C6,9 C7, 30, 04, 08, 09,, C37 Cl C,5 C7,9, Sup 9: * 5: : 8: 8: 5: 5: /0/9

17 . T - ELECTRONICS Replacement Parts List VIDEO DISTRIBUTION AMPLIFIER VA-00NC Page 3 of 4! Part No. Description. Qty Get Ref. Sup! * N448 N4004 BZT03C68 BZX79C5 LEDGN5MM N3904 N3906 N N905 N907 N4959 N CA3080 LM30N UM95 IM- 4.7 IM- 0 IM- 00 IM P ZTMJB505 70B DIODE 75V 00mA DIODE POWER A DIODE ZENER 68V DIODE ZENER 5V LED GREEN HF TRANS TO-9 NPN HF TRANS TO-9 PNP HF TRANS TO- 8 NPN HF TRANS TO-39 PNP HF TRANS TO-8 PNP RF TRANS TO- 8 PNP RF TRANS TO-39 NPN C REGULATOR V A C REGULATOR -V A OPERATIONAL TRANS COND AMP OP AMP BUFFER DC/DC CONVERTER 48/x5 INDUCTOR 4.7uH INDUCTOR louh INDUCTOR loouh INDUCTOR 50uH CONNECTOR 4 PIN PC HEADER PC HEADER (GOLD) SHORTING LINKS 30u GOLD HEAT SINK Dll-5 Dl D D0 LD, Ql,,6,7,,3,5,6 Qll,4 Q4 Q0 Q5 Q3,8 Q9 U5 U6 U3 U4 XI L3-7 L9,0,ll LI L PL PL,3 LK 8: 8: 5: 5: 5: 97: 97: 97: 97: 97: 97: 97: 97: 97: 54: 8: 8: 54: 54: 54: 54: J 99: 99: 99: 8: /0/9

18 - R. T ELECTRONICS. H.TD.! Part No. E80383 W308T L46 0x5.50 SL SBV700/4/6 SNU/050/7/4 Replacement Parts List VIDEO DISTRIBUTION AMPLIFIER VA-00NC Page 4 of 4 Description. ESCUTCHEON C SOCKET 8 PIN OPEN FUSE HOLDER (PCB) FUSE 50mA LED HOLDER KNOB BLACK WITH LINE CAP BLACK WITH LINE CO-AXIAL CABLE HANDLE S/W COVER S/W MODULE FRAME S/W MODULE SIDE COVER BRASS STUD "U" NUTS Qty.3 Get Ref. SupJ /0/9

19 T* m JL! Part No. Replacement Parts List 8080 REAR ASSEMBLY RB-N ISSUE Page of S AC40334-A76-A PC80957 PC CAP SCREW 4BA Description. CONNECTOR 4 PIN S CONNECTOR COAXIAL.5/6 TERMINAL BLOCK PCB I/P LOOP COMP REAR PLATE RB-lN CHASSIS REAR ASSY S/W SIDE PLATE REAR ASSY SCREW ALLEN HEAD 4BA BLK Qty 8 i Jl TB LI Get Ref. Sup * 54: 86: 6: 68: 6: 6: 6: 4 : //87

IRT Eurocard. Type AG-738. Stereo Audio Phase / Failure Detector

IRT Eurocard. Type AG-738. Stereo Audio Phase / Failure Detector I R T Electronics Pty Ltd A.B.N. 000 7 6 Hotham Parade, ARTARMON N.S.W. 06 AUSTRALIA National: Phone: (0) 7 Fax: (0) 7 International: +6 7 +6 7 Email: sales@irtelectronics.com Web: www.irtelectronics.com