Zanussi 22ZT907 Service Manual

CHASSIS PICTURE TUBE POWER SUPPLY POWER ABSORBED EHT MAX. BEAM CURRENT ANTENNA INPUT TUNER TUNING SYSTEM PRESELECTION

AFC REMOTE CONTROL REMOTE CONTROL

TRANSMITTER In stand-by

ABSORPTION

CLOCK AUXILIARY OUTPUT JACKS

LOUDSPEAKER AUDIO OUTPUT STANDARD DEGAUSSING DIMENSIONS WEIGHT

GENERAL FEATURES

:

BS 400.2

:

22" PIL s 4

.

240V AC + 10% 50 Hz

:

Medium/maximum

:

.

24.5

1.1

kV

InA

-

A 56-701

110/140

W

X

: 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.

<

20

/uA

In operation < 9

{

:

Electronic programmable type with

mA

8

m

digital hours and minutes indication

:

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

:

Automatic

:

55x55~42

.

29

kg

-

I PAL

cm

-l-

.

CONTROLS ON THE TV RECEIVER

Front controls

1. Electronic clock

.2.

Control panel

3.

Switch-ON & programme

*cover

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

26.

Headphones jack

foldback

release

-2-

Rear sockets

27. Auxiliary speaker jack

28. Aerial socket

29.

Clock battery recess

-3-

ACCESS TO INTERNAL COMPONENTS

To remove back panel:

1. Insert a blade screwdriver into

2. Push down retaining lug

3.

Release bottom part and remove panel.

“B”

;

"A";

-a_

.

VIEW OF CHASSIS AND OF DISCONNECTD PLUG-IN TYPE P.C.BOARDS

BS 400

BS 417

BS 397 BS

398

BS

399

BS 4

.a

LEGEND

BS

395

396

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.

CRT discharger

separator and pincushion correction p.c.b.

p.c.b.

Video p.c.b.

IF unit p.c.b.

Vertical deflection p.c.b.

A

-5-

*. .-

REFERENCES FOR MAIN ADJUSTMENTS

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

P

401

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 Potentiometer for adjustment of

of

+12.6v

+15OV

DC

*.

Oscillator frequency adjustment potentiometer Pincushion adjustment potentiometer

Horizontal amplitude adjustment potentiometer

-6-

BS BS BS BS BS

P

P P P P L

C

395

396

397

398

399

108

109

106 107 104 105 103 102 123

Line output Synchro. Vertical deflection

p.c.b.

separator and pincushion correction p.c.b.

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

TRANSISTORS

Transistors mounted on chassis and p.c.boards

Transistors

Tl

T3

T4 T6

T7 T8

101

T T102

103

T

104

T

105

T

106

T

107

T

108

T

109

T

110

T

261

T

262

T

263

T

264

T

265

T

266

T

301

T

302

T

303

T

351

T

352

T

353

T

354

T

355

T

402

T

403

T

404

T

451

T

452

T

Type

BF 479 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 BC 548 BC 548 B BC 548 BC 558 B

BD

679 BF 758 BU 208 A

S

A B

C

Electronic functions UHF amplifier

Oscillator/convertor UHF UHF amplifier IF amplifier Audio amplifier Impedance matcher Automatic control of

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

p.p.

luminance

-8-

TRANSISTORS

.

Transistors mounted on remote control and tuning unit

Transistors

T 702

T 704

T

705 T 801 T 802 T 803 T 804

T 805

T 806 T

807

T 808

809

T

Type

BC 547 B

Electronic functions

Driver for DL 651

BC 547 B AFC enabler

BC 547 B BC 413 C BC 413 C BC 413 C BC 253 C

BC 170 C BC 320 B BC 320 B BC 320 B

BC 548

B

Clipper AGC Amplifier Amplifier Amplifier

Square-wave shaping

Driver for display's lit spot Driver for display's lit spot Driver for display's lit spot

Colour adjustment

T

8i0

811

T

812

T

813

T

T 814 T 815

BC 548 B

BC

320

BC 548

Volume adjustment B

B

Muting

Output impedance matcher

-Y-

INTEGRATED CIRCUITS

ICs

mounted on chassis and p.c.boards

:cs

CI

1

CI

2

CI

201

101

102

103

Type

TDA 2541

TBA 120 U

TDA 2151

TDA 2140

TDA 2161

TDA 4290

Electronic functions

IF amplifier. Carrier generator and synchronous detector. Video preamplifier. White peaks inverter stage

-

AGC - AFC.

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.

R-Y/B-Y demodulators. G-Y matrix. Luminance matrix.

Continuous path control adjustment of

treble, bass and volume.

CI

202

CI 261

CI 262

CI

301

CI

351

CI

401

TDA 2030

TDD 1618

MC

14013

L 200 v TDA 1170

S

TDA 2593

Audio amplifier.

l8V

stabilizer.

Switch-ON reset. TV start signal

24h

clamp pulse.

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.

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-

.

BS 400.2 Chassis

BS

398

Tuner - IF video/audio

p.c.b.

BS

399

Luminance-chrominance and

video amplifier

MAIN COMPONENTS

-

It supports the p.c.boards and

-

Conversion of the RF signal into

-

This p.c.b. processes the

p.c.b.

it supplies voltages for EHT, focusing system and CRT heaters.

an IF signal (video carrier:

39.5 MHz;,

33.5 MHZ).

audio carrier:

Detection of the IF signal into

low frequency video and audio signals.

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.

BS 470 Mains filter 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.

-

The p.c.b.

includes circuits relevant to: mains filter, degaussing, remote control

SUPPlY,

start remote control.

BS

380

Power supply p.c.b.

No adjustments needed.

-

It includes circuits for

clock supply and for switch-ON programming.

No adjustments needed.

-12-

BS

417

BS

Power supply p.c.b.

397

Vertical deflection

p.c.b.

-

It converts the mains voltage in

DC voltage available at five outputs with values of:

+15OV; +27V

+12.6v.

(two outputs);

These voltages are

+2OOV;

stabilized and separated from the mains.

-

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

synchro.

section of the

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.

BS

395

Horizontal deflection

p.c.b.

BS 418 CRT 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.

-

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.

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.

BS

387

IR preamplifier

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.

-

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.

BS 405 Front control unit 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.

-

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,

and tuning indicating

bachward

tuning, band

LEDs.

-14-

BS

388

Tuning unit p.c.b.

BS 414 a/b Remote control

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

indication with five

LEDs.

Tuning level

LEDs.

Memorization of 16 selected programmes manually or with remote control.

No adjustments needed.

-

This p.c.b. enables remote

control of the following

functions: selection of

"+"

or

programmes;

"-"

16

volume adjustment; brightness and saturation adjustment; audio silencing; TV receiver ON/OFF switching.

No adjustments needed.

-?5-

ADJUSTMENT PROCEDURE

PCB BS

Denomination

398

:

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~

-

Sweep generator,

-

Dual trace oscilloscope - 10 MHz

-

200 mA power supply.

>lO

MHz and

markers at:

36.5, 39.5,

31.5,

41.5

33.5, 35.1.

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 signal, 20% white level - 76% black level. Audio carrier modulated at 1 with + 50 50

/us

kHz

of deviation at

of preemphasis.

kHz

-

Note: See legend of test points

(TP)

Voltmeter

at the end of adjustment

(15V

setting).

procedure.

Preliminary operations:

-

Supply the p.c.b. with

-

Adjust the varicap voltage to 26V (terminal B 1).

-

Position the wipers of P 1 and P 2 towards earth so as to have

12.6V

at terminal A 9.

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

-q--q

Adjustment of RF unit output filter

l-

Adjust corresponding to best coupling and balancing:

L40

and

______.:-

SFD104

ADJUSTMENTS

L49

for a curve as that shown in figure,

37.125Mt-k

390

r&

-----

-- -_

1

-I&

*

2 -

_-

_--

-

30MHz

---

------

--

J

\-

_---

Disconnect the probe from collector of T6.

----

_--_-----

-IT-

-----

-3d6

Adjustment of reference circuit

Connect the oscilloscope's probe to video output (A

1

-

Connect the IF signal (complete of modulated audio) at 10

2-

6).

on TP 1.

Adjust L44 for minimum amplitude of demodulated signal,

3-

corresponding to the best response transients or to 2 T pulse.

Adjust the

Adjust

l-

6 MHz

L46

trap and the audio input filter

and L48 for lowest output of 6 MHz signal present in

video,signal.

Adjustment of audio quadrature coil

Move the oscilloscope's probe to pin 8 TBA 120 U

l-

Give a max. 12V bias to the volume control terminal A 2.

2-

Connect a 10

3-

+12V

and read the DC voltage.

Disconnect the 10

4-

kOhm

resistance between pin

kOhm

resistance.

13

of TBA 120 U and the

(LF

audio output).

mV

level

Adjust L47 until the DC voltage corresponds again to value measured

5-

previously.

Audio adjustment

Move

l-

2-

3-

the oscilloscope probe to terminal A 3.

Maintain on the TP 1 the IF signal with modulated audio carrier.

Adjust P 2 so as to obtain on the A 1 terminal the signal VA

3

2.2+0.2 vpp

=

0.7820.07

V

RMS.

AFC adjustment

Bias the AFC

l-

towards

Connect a voltmeter to AFC output pin A 12.

2-

Adjust L45 for an intermediate value (approx. 2V) in range of

3-

values that go from

output by means of two 100 and the other towards earth.

+12V

to 0 V.

kOhm

resistances

;

one

-18-