Zanussi 22ZT907 User manual

TIP
ZANUSSI
ZANUSSI
Model / Chassis
22ZT907
BS-400.2 CHASSIS
ZANUSSI
SERVICE MANUAL

ZANUSSI
SERVICE DEPARTMENT
SETCO/ACF
Model
22 ZT 907
C. 430-2-1982
(UK) (54)
Zanussi Elettrorrica S.p.A. reserve all legal rights
to the exclusive ownership of this document and
hereby prohibit reproduciion or disclosure of the
same without their prior permission.
. :
*
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CONTENTS
- GENERAL FEATURES ....................... 1
- CONTROLS ON THE RECEIVER ............... 2
- ACCESS TO INTERNAL COMPONENTS .......... 4
- VIEW OF CHASSIS AND OF DISCONNECTED
PLUG-IN TYPE P.C.BOARDS ............... 5
- REFERENCES FOR MAIN ADJUSTMENTS ........ 6
- TRANSISTORS
............................ 8
- INTEGRATED CIRCUITS .................... 10
- MAIN COMPONENTS ........................ 12
- ADJUSTMENT PROCEDURE ................... 16
- TELETEXT TRANSMITTER ................... 24
- PROCUCT SAFETY NOTICE ................. 33

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GENERAL FEATURES
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CHASSIS
PICTURE TUBE
POWER SUPPLY
POWER ABSORBED
EHT
MAX. BEAM CURRENT
: BS 400.2
: 22" PIL s 4
- A 56-701 X
.
.
240V AC +10% 50 Hz
:
Medium/maximum 110/140 W
:
24.5 kV
.
.
1.1 InA
ANTENNA INPUT
TUNER
TUNING SYSTEM
PRESELECTION
AFC
REMOTE CONTROL
REMOTE CONTROL
ABSORPTION
CLOCK
: 75 Ohm
.
.
Varicap integrated type
.
.
Electronic (voltage synthesis type)
.
.
16 TV programmes and VCR on programme
16
:
Insertable through pushbutton
.
.
{
IR type. Max. range approx. 8 m
TRANSMITTER In stand-by
< 20 /uA
In operation < 9 mA
: Electronic programmable type with
digital hours and minutes indication
AUXILIARY OUTPUT JACKS
LOUDSPEAKER
AUDIO OUTPUT
STANDARD
DEGAUSSING
DIMENSIONS
WEIGHT
: Headphones jack 8 Ohm DIN 45327
Tape recorder 47 kOhm DIN 41524
External loudspeaker jack 2.7 Ohm
DIN 41529
: Lateral woofer and frontal tweeter
.
.
15 W
.
.
CCIR
- I PAL
: Automatic
: 55x55~42 cm
.
.
29 kg
.
-l-
.
. *-
*. .-

CONTROLS ON THE TV RECEIVER
Front controls
1. Electronic clock
.2. Control panel *cover
3. Switch-ON & programme
sequential channel change
control
4. Digital programme dispaly
5. Stand-by switch
6. Output jacks recess cover
7. Remove control receiver
8. Clock brightness control
9. Clock reset - hours H
10. Clock reset - minutes M
11. Volume
12. Tone control - treble
13. Tone control - bass
14. Brightness
15. Colour control
16. Contrast
17. Clock programmer
18. UHF band indicator light
19. AFC indicator light
20. AFC pushbutton
21. Station scanning control - S
22. Fine tuning regulation
23. Tuning sequence lights
24. Recording jack
25. Output jacks foldback release
26. Headphones jack
-2-

Rear sockets
27. Auxiliary speaker jack
28. Aerial socket
29. Clock battery recess
-3-

_‘.
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ACCESS TO INTERNAL COMPONENTS
To remove back panel:
1. Insert a blade screwdriver into "A";
2. Push down retaining lug “B” ;
3. Release bottom part and remove panel.
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BS 397
BS 398
BS 399
BS 4 .a
VIEW OF CHASSIS AND OF DISCONNECTD PLUG-IN TYPE P.C.BOARDS
BS 400
LEGEND
BS 400.2
BS 417
BS 395
BS 396
BS 418
BS 399
BS 398
BS 397
Chassis
Power supply p.c.b,
Line output p.c.b.
Synchro.
separator and pincushion correction p.c.b.
CRT discharger p.c.b.
Video p.c.b.
IF unit p.c.b.
Vertical deflection p.c.b. A
BS 417
BS 395
BS 396
*. .-
-5-

REFERENCES FOR MAIN ADJUSTMENTS
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s 417
P 303
301
LEGEND
Pl
P 351
P 352
P 353
P 354
P 551
BS 418
SW 553
SW 552
P 552
SW 551
BS 417
.P 303
P 301
P 401
P 402
P 403
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.
Switch for blue electron gun
Switch for green electron gun
Focus adjustment potentiometer
Switch for red electron gun
Power supply p.c.b.
Potentiometer for adjustment of +12.6v DC
Potentiometer for adjustment of +15OV DC
Oscillator frequency adjustment potentiometer
Pincushion adjustment potentiometer
Horizontal amplitude adjustment potentiometer
P 401
402
P 403
*. .-
-6-

BS 395
BS 396
BS 397
BS 398
BS 399
P 108
P 109
P 106
P 107
P 104
P 105
P 103
L 102
C 123
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)
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
Capacitive trimmer for oscilloscope adjustment

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TRANSISTORS
Transistors mounted on chassis and p.c.boards
Transistors
Tl
T3
T4
T6
T7
T8
T
101
T102
T103
T
104
T105
T
106
T107
T
108
T
109
T
110
T
261
T
262
T
263
T
264
T
265
T
266
T301
T
302
T
303
T351
T
352
T
353
T
354
T
355
T
402
T
403
T
404
T451
T
452
Type
BF 479 S
BF 680
BF 506
BF 199
BC 548 B
BC 548 B
BC 548 B
BC 548 B
BC 548 B
BC 548 B
BF 393
BF 758
BF 393
BF 758
BF 393
BF 758
TIL 78
BC 548 B
BC 548
BC 320 B
BC 548 B
BC 320 B
BC 557 B
BU 326 A
BC 548 B
BD 135
BD 243 A
BD 244 A
BC 548 B
BC 548 B
BC 548 C
BC 558 B
BD 679
BF 758
BU 208 A
Electronic functions
UHF amplifier
Oscillator/convertor UHF
UHF amplifier
IF amplifier
Audio amplifier
Impedance matcher
Automatic control of p.p. luminance
signal
Brightness control fixed level setting
for adjustment of the output video
amplifiers
T 101 driver
Suppressor of unwanted reflections on
the burst signal delay line LR 102 of
the chrominance channel
Active load
Video output
Active load
Video output
Active load
Video output
Optoelectric coupler
Amplifier
Switching transistor
Switching transistor
Driver for optoelectric coupler
Driver for optoelectric coupler
Amplifier
Oscillator
Switch for remote control
Switching transistor
Vertical parabola amplifier
Vertical parabola amplifier
Multivibrator for formation of vertical
blanking pulse
Parabola signal amplifier
Parabola signal amplifier
Amplifier
Amplifier switch
Line output
-8-

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TRANSISTORS
.
Transistors mounted on remote control and tuning unit
Transistors
Type
Electronic functions
T 702
BC 547 B Driver for DL 651
T 704 BC 547 B AFC enabler
T 705
BC 547 B Clipper
T 801
BC 413 C AGC
T 802
BC 413 C Amplifier
T 803 BC 413 C Amplifier
T 804 BC 253 C Amplifier
T 805 BC 170 C
T 806
BC 320 B
T 807
BC 320 B
T 808
BC 320 B
Square-wave shaping
Driver for display's lit spot
Driver for display's lit spot
Driver for display's lit spot
T
809
T 8i0
T
811
T
812
T
813
BC 548
B
BC 548 B
BC 320
B
BC 548
B
BC 548
Colour adjustment
Volume adjustment
Muting
Muting
Output impedance matcher
T 814
T 815
BC 548
BC 548
Output impedance matcher
Output impedance matcher
-Y-

INTEGRATED CIRCUITS
ICs mounted on chassis and p.c.boards
:cs
CI 1
CI 2
CI 101
CI 102
CI 103
CI 201
TDA 4290
CI 202
CI 261
CI 262
CI 301
CI 351
CI 401
TDA 2151
TDA 2140
Type
TDA 2541
Electronic functions
IF amplifier. Carrier generator and
synchronous detector. Video preamplifier.
White peaks inverter stage - AGC - AFC.
TBA 120 U Amplifier/limiter. Coincidence detector.
Reference frequency generator for
detection. Low frequency audio signal
output with insertion of volume
adjustment. Low frequency audio signal
output without volume adjustment.
Luminance/chrominance signal processing.
Brightness,
contrast and colour controls.
Beam current limiter.
Colour subcarrier regeneration. PAL
switching. Identifier. Killer. AFC and
automatic phase control. ACC. Burst.
TDA 2161
R-Y/B-Y demodulators. G-Y matrix.
Luminance matrix.
Continuous path control adjustment of
treble, bass and volume.
TDA 2030
TDD 1618
MC 14013
Audio amplifier.
l8V stabilizer.
Switch-ON reset. TV start signal 24h
clamp pulse.
L 200 v
TDA 1170 S
12.6V stabilizer.
Square-wave signal generation. Conversion
of the square-wave signal into a
saw-tooth signal. Saw-tooth signal
amplification. Voltage stabilization
of all internal circuits.
TDA 2593 Synchro. separator. Phase comparator.
15625 Hz oscillator. Phase shift.
Generator of the driving pulse for the
line output amplifier. Sand-castle
generator.
*. .-
-lO-

INTEGRATED CIRCUITS
ICs mounted on remote control and tuning unit
ICS
CI 651
CI 701
CI 702
CI 703
CI 704
CI 705
CI 706
CI 707
CI 708
CI 801
CI go1
Type
MC 14493 P
MC 14426
MC 14426
MC 14429
UAA 1008
4071 BE
4049 D
4013
SN 16889 P
SAA 1051
SAA 1050
Electronic functions
It drives DI 651 display
Memory for 8 programmes
Memory for 8 prograinmes
Control unit
Band decoder. Coincidence detector.
Operational amplifier. AFC processing.
Two-input OR
Inverting buffer
Double flip-flop
Tuning indicator
It processes information coming from
remote control.
Remote control transmitter
.
-ll-
*. .-

MAIN COMPONENTS
BS 400.2 Chassis
BS 398 Tuner - IF video/audio
p.c.b.
- It supports the p.c.boards and
it supplies voltages for EHT,
focusing system and CRT heaters.
- Conversion of the RF signal into
an IF signal (video carrier:
39.5 MHz;, audio carrier:
33.5 MHZ).
Detection of the IF signal into
low frequency video and audio
signals.
BS 399 Luminance-chrominance and
- This p.c.b. processes the
video amplifier p.c.b.
complete composite video signal
coming from the IF p.c.b. and
supplies the R-G-B signals to
the picture tube.
BS 401 Audio p.c.b.
- This p.c.b.
receives the audio
signal (not adjusted in volume)
coming from p.c.b. BS 398, it
adjusts it in amplitude and
tone, it amplifies it and sends
it to drive the two receiver's
loudspeakers (tweeter and
woofer).
Through jack PR 201 it is
possible to connect externally
an auxiliary 2.7 Ohm loudspeaker
with or without the exclusion
of the internal loudspeakers.
Furthermore, the p.c.b.
transferes the audio signal
(not adjusted in volume) to
taperecorder and headphone
jacks.
No adjustments needed.
BS 470 Mains filter p.c.b.
BS 380 Power supply p.c.b.
- The p.c.b. includes circuits
relevant to: mains filter,
degaussing, remote control
SUPPlY,
start remote control.
No adjustments needed.
- It includes circuits for
clock supply and for switch-ON ~
programming.
. .-
*._
No adjustments needed.
-12-

BS 417 Power supply p.c.b.
- It converts the mains voltage in
DC voltage available at five
outputs with values of: +2OOV;
+15OV; +27V (two outputs);
+12.6v. These voltages are
stabilized and separated from
the mains.
BS 397 Vertical deflection p.c.b.
- This p.c.b. generates a sawtooth
voltage at frame frequency which
is used for driving the vertical
deflection yoke. It supplies a
similar voltage to the
l'pincushionll section of the
synchro.
separator p.c.b. to
obtain the E/W pincushion
correction.
It supplies a frame frequency
pulse which is used for the
luminance,
chrominance and video
amplifier p.c.b. blankings. It
receives the vertical synchro.
from the synchro. separator
p.c.b. and receives from the
chassis a voltage proportional
to the beam current.
BS 396 Synchro. separator and
pincushion correction
p.c.b.
- The p.c.b. processes the video
signal. Said process consists in
separating the horizontal
signals from the video composite
signal. The "pincushion
correctionl' section receives a
sawtooth shaped signal and
converts it into a parabolic
shape for E/W correction.
BS 395 Horizontal deflection
p.c.b.
- This p.c.b.
amplifies the pulse
sequence at line frequency and
drives a circuit operating as
an ON-OFF switch for supplying
the deflection current to the
horizontal yoke. It also
receives the parabolic signal
which acts on the diodes
modulator for E/W correction.
No adjustments needed.
BS 418 CRT p.c.b.
It includes protection and
matching circuits for the three
signals (red, green and blue) ;~ .-
with relevant voltage
*
._
dischargers. In series to each
signal circuit a switch is
provided for black level
adjustment.

The p.c.b. includes a cut-OFF
circuit which stops the CRT
luminous emission during the
blanking phase.
BS 385 Auxiliary outputs jacks
p.c.b.
- This p.c.b.
receives the audio
signal (amplified and volume
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.
The headphones output complies
to Standard DIN-45327 and has an
impedance of 8 Ohm. The
taperecorder output complies to
Standard DIN-41524 and has an
impedance of 47 k0hm.
No adjustments needed.
BS 387 IR preamplifier p.c.b.
- It converts IR pulses coming
from the transmitter into
electrical pulses. These are
amplified and appropriatly
clipped.
No adjustments needed.
BS 389 Remote control receiver
p.c.b.
- It receives the command signals
coming from the sequential
programme pushbutton, it
processes them and converts them
into control signals. Tone and
contrast controls also pass
through this p.c.b., said
control signals being fed from
the control unit and being
forwarded to the chassis.
No adjustments needed.
BS 405 Front control unit p.c.b.
- This p.c.b. includes
potentiometers for volume,
brightness, saturation,
contrast, treble and bass.
This p.c.b. also includes
pushbuttons relevant to
sequential control, AFC,
automatic search, forward
tuning, bachward tuning, band
and tuning indicating LEDs.
-14-

BS 388 Tuning unit p.c.b.
The display indicates the
programme selected. Furthermore,
this p.c.b. includes all
pushbuttons for clock
adjustment.
No adjustments needed.
- Automatic searching of a TV
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.
Band indication displayed on
three LEDs. Tuning level
indication with five LEDs.
Memorization of 16 selected
programmes manually or with
remote control.
No adjustments needed.
BS 414 a/b Remote control p.c.b.
- This p.c.b. enables remote
control of the following
functions: selection of 16
programmes;
"+" or "-" volume
adjustment; brightness and
saturation adjustment; audio
silencing; TV receiver ON/OFF
switching.
No adjustments needed.
*. .-
-?5-

ADJUSTMENT PROCEDURE
PCB BS 398
Denomination
: Tuner IF video/IF audio
Adjustment procedure for IF section
Instruments used:
- 0 to 30V adjustable power supply.
- 0 to 12V adjustable power supply.
- 12.6~ - 200 mA power supply.
- Sweep generator, >lO MHz and
markers at: 31.5, 33.5, 35.1.
36.5, 39.5, 41.5 and 37.1125 MHz
for adjustment of output filter.
- Dual trace oscilloscope - 10 MHz
pass-band.
IF signal (video carrier
39.5 MHz and audio carrier
33.5 MHz) with 100% standard
video modulation, bar modulating
signal, 20% white level - 76%
black level.
Audio carrier modulated at 1 kHz
with + 50 kHz of deviation at
50 /us of preemphasis.
- Voltmeter (15V setting).
Note: See legend of test points (TP) at the end of adjustment procedure.
Preliminary operations:
- Supply the p.c.b. with 12.6V at terminal A 9.
- Adjust the varicap voltage to 26V (terminal B 1).
- Position the wipers of P 1 and P 2 towards earth so as to have
connected the maximum resistance.
.
-16-

Connect the sweep generator with a probe (see figure below) to TP 1:
1OnF
Connect a high impedance detector probe on collector of T6. See figure
below:
6PF
SFD104
390 r&
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1
ADJUSTMENTS
Adjustment of RF unit output filter
l-
Adjust L40 and L49 for a curve as that shown in figure,
corresponding to best coupling and balancing:
37.125Mt-k
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30MHz
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*. .-
2 -
Disconnect the probe from collector of T6.
-IT-