Download Table of Contents Print this page

Zanussi 22ZT907 Service Manual


Quick Links

Model / Chassis


Table of Contents

Summary of Contents for Zanussi 22ZT907

  • Page 2 ZANUSSI DEPARTMENT SERVICE SETCO/ACF Model 22 ZT 907 to the exclusive ownership of this document and C. 430-2-1982 hereby prohibit reproduciion or disclosure of the same without their prior permission.
  • Page 3: Table Of Contents

  • Page 4: General Features

    GENERAL FEATURES CHASSIS BS 400.2 PICTURE TUBE 22" PIL s 4 - A 56-701 X POWER SUPPLY 240V AC + 10% 50 Hz POWER ABSORBED Medium/maximum 110/140 W 24.5 kV 1.1 InA MAX. BEAM CURRENT ANTENNA INPUT : 75 Ohm TUNER Varicap integrated type TUNING SYSTEM...
  • Page 5: Controls On The Receiver

    CONTROLS ON THE TV RECEIVER Front controls 1. Electronic clock Switch-ON & programme sequential channel change control 4. Digital programme dispaly 5. Stand-by switch 6. Output jacks recess cover Remove control receiver 8. Clock brightness control 9. Clock reset - hours H 10.
  • Page 6 Rear sockets 27. Auxiliary speaker jack 28. Aerial socket...
  • Page 7: Access To Internal Components

    ACCESS TO INTERNAL COMPONENTS To remove back panel: 1. Insert a blade screwdriver into 2. Push down retaining lug “B”...
  • Page 8: View Of Chassis And Of Disconnected Plug-In Type P.c.boards

    VIEW OF CHASSIS AND OF DISCONNECTD PLUG-IN TYPE P.C.BOARDS BS 400 BS 417 BS 399 BS 4 LEGEND BS 400.2 Chassis BS 417 Power supply p.c.b, Line output p.c.b. Synchro. separator and pincushion correction p.c.b. BS 396 BS 418 CRT discharger p.c.b. Video p.c.b.
  • Page 9: References For Main Adjustments

    REFERENCES FOR MAIN ADJUSTMENTS s 417 LEGEND AGC adjustment potentiometer Vertical linearity adjustment potentiometer Vertical frequency adjustment potentiometer Vertical amplitude adjustment potentiometer Raster adjustment potentiometer Potentiometer for (grid-2) adjustment of picture tube CRT discharger p.c.b. SW 553 Switch for blue electron gun Switch for green electron gun Focus adjustment potentiometer SW 551...
  • Page 10 Line output p.c.b. Synchro. separator and pincushion correction p.c.b. Vertical deflection p.c.b. IF unit p.c.b. Video p.c.b. Peak-to-peak adjustment potentiometer (blue) Black level adjustment potentiometer (blue) P 109 Peak-to-peak adjustment potentiometer (green) Black level adjustment potentiometer (green) Peak-to-peak adjustment potentiometer (red) Black level adjustment potentiometer (red) Potentiometer for adjustment of direct signal level Burst phase adjustment coil...
  • Page 11: Transistors

    TRANSISTORS Transistors mounted on chassis and p.c.boards Electronic functions Transistors BF 479 S UHF amplifier Oscillator/convertor UHF BF 680 UHF amplifier BF 506 IF amplifier Audio amplifier BC 548 B Impedance matcher BC 548 B Automatic control of p.p. luminance T 101 BC 548 B signal...
  • Page 12 TRANSISTORS Transistors mounted on remote control and tuning unit Electronic functions Transistors Type Driver for DL 651 T 702 BC 547 B AFC enabler T 704 Clipper BC 547 B BC 413 C T 801 Amplifier BC 413 C 8 0 2 Amplifier BC 413 C T 803...
  • Page 13: Integrated Circuits

    INTEGRATED CIRCUITS Electronic functions IF amplifier. Carrier generator and TDA 2541 synchronous detector. Video preamplifier. White peaks inverter stage - AGC - AFC. Amplifier/limiter. Coincidence detector. TBA 120 U Reference frequency generator for detection. Low frequency audio signal output with insertion of volume adjustment.
  • Page 14 INTEGRATED CIRCUITS Electronic functions MC 14493 P It drives DI 651 display MC 14426 Memory for 8 programmes Memory for 8 prograinmes MC 14426 CI 702 MC 14429 Control unit UAA 1008 Band decoder. Coincidence detector. Operational amplifier. AFC processing. Two-input OR 4071 BE Inverting buffer...
  • Page 15: Main Components

    MAIN COMPONENTS BS 400.2 Chassis it supplies voltages for EHT, focusing system and CRT heaters. BS 398 Tuner - IF video/audio an IF signal (video carrier: p.c.b. audio carrier: Detection of the IF signal into low frequency video and audio signals.
  • Page 16 Power supply p.c.b. DC voltage available at five outputs with values of: +2OOV; These voltages are stabilized and separated from the mains. BS 397 Vertical deflection p.c.b. voltage at frame frequency which is used for driving the vertical deflection yoke. It supplies a similar voltage to the synchro.
  • Page 17 The p.c.b. includes a cut-OFF circuit which stops the CRT luminous emission during the blanking phase. Auxiliary outputs jacks signal (amplified and volume p.c.b. adjusted) and supplies it to an auxiliary jack for private headphone listening. A non-volume-regulated signal is also supplied to a socket for taperecording.
  • Page 18 The display indicates the programme selected. Furthermore, this p.c.b. includes all pushbuttons for clock adjustment. No adjustments needed. Tuning unit p.c.b. station through a start command. Manual searching of a TV station through two commands (increment and decrement). Inclusion-exclusion of the AFC circuit with LED display.
  • Page 19: Adjustment Procedure

    ADJUSTMENT PROCEDURE PCB BS 398 Tuner IF video/IF audio Denomination Adjustment procedure for IF section Instruments used: 200 mA power supply. markers at: 31.5, 33.5, 35.1. 36.5, 39.5, 41.5 and 37.1125 MHz for adjustment of output filter. pass-band. IF signal (video carrier 39.5 MHz and audio carrier 33.5 MHz) with 100% standard video modulation, bar modulating...
  • Page 20 Connect the sweep generator with a probe (see figure below) to TP 1: Connect a high impedance detector probe on collector of T6. See figure below: 390 r& ADJUSTMENTS Adjustment of RF unit output filter Adjust L40 and L49 for a curve as that shown in figure, corresponding to best coupling and balancing: Disconnect the probe from collector of T6.
  • Page 21 Adjustment of reference circuit Connect the oscilloscope's probe to video output (A Connect the IF signal (complete of modulated audio) at 10 mV level on TP 1. Adjust L44 for minimum amplitude of demodulated signal, corresponding to the best response transients or to 2 T pulse. 6 MHz Adjust the trap and the audio input filter...
  • Page 22 Adjustment of the AGC voltage for RF unit Connect a voltmeter to TP 5. With the signal at 15 mV video IF, adjust P until voltage is reduced to 8V. Correspondence between TP (test point) and wiring diagram -1 g-...
  • Page 23 PCB BS Luminance-chrominance and video Denomination output amplifier. Adjustment procedure Preliminary operations 25OmV on contact Check that the p.c.b. is correctly supplied: F12; +2OOV DC + 1OV on contact G5; +2.2V DC + 1OOmV on contact Fl; 12 Vpp on contact F14; 160 Vpp on contact G2; 11 Vpp on contact FlO. Brightness and contrast controls to maximum (adjustment on remote control when provided).
  • Page 24 Grey-scale alignment Grey-scale signal in antenna (or an equivalent signal). Saturation to minimum. Correct tuning. Disconnect SW501. Slowly adjust P551 so as to obtain a horizontal line slightly lit (it's advisable to operate in low environmental lighting conditions). Keeping as reference the colour of the prevailing electron gun of this line, accurately adjust black-level potentiometers of the other two electron guns (P105 for red, P107 for green, P109 for blue) until the horizontal line is perfectly white.
  • Page 25 PCB BS Synchro. separator and pin-cushion Denomination correction. Adjustment procedure Synchro. separator alignment until the picture slowly drifts horizontally. Disconnect bridge S 401. Pincushion alignment are straight. PCB BS Picture tube Denomination Adjustment procedure Switches for exclusion of picture tube electron SW 551-552-553 guns.
  • Page 26 PCB BS Vertical deflection Denomination Adjustment procedure Test signal in antenna. Adjust P 352 to obtain a correct frame synchronization. Grossly adjust vertical centering and linearity (P 351). Adjust P 354 for correct picture centering. Adjust P 353 to obtain a correct vertical amplitude. Adjust P 351 to obtain the best vertical linearity.
  • Page 27: Teletext Transmitter

    TELETEXT TRANSMITTER TELETEXT FUNCTIONS Switches the system into the teletext mode MIX - HOLD - TEXT BOTTOM - CANCEL and STATUS become operative. The commands for the brightness, volume, saturation, muting in the Text mode are all operative and this is useful in MIX.and CANCEL operations.
  • Page 28 Press the CANCEL button and the normal TV programme will return with the Teletext page Header superimposed for seconds. At the selected alarm time, the alarm page header will re-appear. This page remains stored in the memory until the TP-OFF command is pressed. Cancels TP-ON TP-OFF - HOLD...
  • Page 29 Transistors used on teletext p.c.b. Electronic functions Transistors Type Video preamplifier BC 548 B Video preamplifier BC 548 B Video input signal switch BC 548 B T3 switch enabler BC 548 B Teletext synchro. switch BC 548 B Synchro. signal emitter follower BC 548 B Command inverter BC 548 B...
  • Page 30 Electronic functions 12V stabilizer A 78 Ml2 C 5V stabilizer 78 MO5 C Programmable adaptor for teletext SAA 1272 A Teletext video processor SAA 5030 - VIP SAA 5041 - TAC Teletext acquisition and control circuit Teletext timing chain circuit CI 6 SAA 5020 - TIC SN 74 LS02N...
  • Page 31 This p.c.b. performs the following main functions: transmitted during the vertical blanking interval; memory (CI 11 and CI 12); in memory (CI forwarded to the CRT (CI set synchro. separator when teletext information is diplayed. The p.c.b. is supplied with +5V and +12V.
  • Page 32 TELETEXT-DECODER ADJUSTMENT The teletext p.c.b. requires three alignment operations which are all relevant to the video input processor SAA 5030. These alignment operations eliminate influence of tolerances both Of video input processor and of its peripherical components. The adjustment procedure need not be repeated any more until no substitutions are carried out and until the same video input processor is used.
  • Page 33 ADJUSTMENT OF QUARTZ CONTROLLED FREQUENCY A Method The free running frequency of the oscillator is adjusted by means of a capacitive trimmer C26T connected in series with the quartz. The oscillator is free running when pin of SAA 5030 circuit is directly connected to +12 V (jumper between TPl and TP2) and pin 7 is connected to +12 V via a 5.6 M Ohm resistance (jumper between TP3 and TP4).
  • Page 34 Tune to a TV station having teletext signals; the signal must be sufficiently strong (>lmV) and free of reflections and interferences of a certain intensity. Select a teletext page with continuous data renewal and damp signal until a few errors appear. Adjust L4T so as to make character errors disappear or for the least number of them.
  • Page 35 ADJUSTMENT OF RGB LEVELS ON TELETEXT P.C.B Adjustment must be carried out before "white adjustment". 1) Adjust P4T and P3T on R and G so that characters reach the 100 V DC level. 2) Adjust P2T on B so that the character reaches the 110 V DC level. Line blanking V DC Fig.
  • Page 36: Procuct Safety Notice

    PRODUCT SAFETY NOTICE Although the main chassis is insulated from mains, part of the power supply chassis bears mains voltage. This therefore should not be connected to earth during servicing. Do not install, remove, or handle the picture tube in any manner unless shatter-proof goggles are worn.
  • Page 37 Manufacturers reserve all legal ri&z to the exclusive ownership of this document and hereby prohibit reproduction or disclosure of the 8ame without their prior permission.
  • Page 39 Teletext...
  • Page 41 489.0...

Table of Contents