Fisher PCR-20-R-2 Service Manual

SERVICE MANUAL Colour Television

FILE NO.

Model No.PC-R20R2
(USA)

Service Ref.No.PC-R20R2-00

SPECIFICATIONS

Receiving System
Colour System
Picture Tube
Ext. Antenna
Ext. In/Out
Speaker
Audio Output
Power Consumption
Dimension

Net Weight

REMOTE CONTROL
Transmitting System
Power Supply
Dimension

Net Weight

Design and specifications are subject to change without prior notice.

: M

NTSC

:
: 20 inch screen
: 75 Ohm Coaxial Cable

Audio/Video -In/Out

:
: (8 Ohm) x 2
: Maximum 3W
: AC 120V 60Hz, 84W
: 525(W) x 510(D) x 464(H)mm/

20.7(W)
: 22.8 kg/50.26lbs

: Infrared
: DC 3V (1.5 x 2)
: 60(W) x 200(L) x 24(D)mm/

2.4
: 100 g(approx)/0.22lbs

x20.1(D) x 18.3(H)inch

(W) x 7.9(L) x 0.9(D)inch

Product Code: 1 113 495 46

Original Version

Chassis Series: 3Y03

Give complete SERVICE REF.NO. for
parts order or servicing. It is shown on
the rating plate at the cabinet back of
the unit.

This T.V. Receiver will not work properly in
foreign countries where the television
transmission system and power source
differ from the design specifications.
Refer to the Specification table.

""

REFERENCE NO. SM 2300011

Contents

Safety Notice..................................................................2

Chassis Block Diagram....................................................3

IC Block Diagram .........................................................4-7

PCB Top Layer .............................................................8-9

Service Adjustments .................................................10-16

Purity and Convergence Adjustment ...............................17

Control Location............................................................18

Input and Output Terminals.............................................19

Operation Instructions...............................................20-21

Mechanical Disassemblies .............................................22

Cabinet Parts List ..........................................................23

Circuit Diagram..............................................................24

Chassis Electrical Parts List.......................................25-33

Safety Notice

SAFETY PRECAUTIONS

1:An isolation transformer should be connected in the power line between the receiver and
the AC line when a service is performed on the primary of the converter transformer of the
set.
2:Comply with all caution and safety-related notes provided on the cabinet back, inside the
cabinet, on the chassis or the picture tube.
3:When replacing a chassis in the cabinet, always be certain that all the protective devices
are installed properly,such as,control knobs, adjustment covers or shields, barriers,isola­ tion resistor-capacitor networks etc.. Before returning any television to the customer,the
service technician must be sure that it is completely safe to operate without danger of
electrical shock.

X-RADIATION PRECAUTION

The primary source of X-RADIATION in television receiver is the picture tube. The picture
tube is specially constructed to limit X-RADIATION emissions. For continued X-RADIATION
protection, the replacement tube must be the same type as the original including suffix
letter. Excessive high voltage may produce potentially hazardous X-RADIATION. To avoid
such hazards, the high voltage must be maintained within specified limit. Refer to this
service manual, high voltage adjustment for specific high voltage limit. If high voltage exce­eds specfied limits, take necessary corrective action. Carefully follow the instructions for
+B1 volt power supply adjustment, and high voltage check to maintain the high voltage
within the specified limits.

PRODUCT SAFETY NOTICE

Product safety should be considered when a component replacement is made in any area
of a receiver. Components indicated by mark in the parts list and the schematic diagram
designate components in which safety can be of special significance. It is particularly
recommended that only parts designated on the parts list in this manual be used for com­ponent replacement designated by mark . No deviations fromresistance wattage or vol­tage ratings may be made for replacement items designated by mark .

-2-

!

!

!

Chassis Block Diagram

SPEAKER-L

SPEAKER-R

AV1/AV2

VIDEO-OUT

CRT

FOUCS

SCREEN

Ic400

IC403

La4285

AV1/AV2 AUDIOIN

HEF4O53BP

La7840

VERTICAL

I c301

RGB AMP

DEFLECTION

HORIZONTAL

FBP

DEFECTION

I c401

HEF4O52BP

V-OUT

40

VIDEO-IN

TV-AUDIO

41

19-21

23

H-OUT

24V

9V/12V

H-FBP

28 27

I c201

SAW.FIL

PRE.AMP

SDA/SCL

RF-AGC

SCL

TUNER

Ic002

SDA

EEPROM

4 5 6 2

11 1 2

40

AFC

VIDEO

29

19

30

LA76814/76810

14-17

110V (B+)

10

R G B Y

V.SYN

H.SYN

22-25

14

21

20

21V5V9V

LC863224A-5V23

27 28

Ic001

POWER

VIDEOIN

-3-

IC Block Diagram

IC 001 (MULTI SYSTEM COLOR TV CPU) LC863224A

-4-

IC Block Diagram

IC 201 (IIC BUS SINGLE CHIP VIF,SIF,VIDEO CHROMA) LA76814K

7.5K

IN

FBP

V/C

VCC

10K

330p

REF

4.7K
MetalFilm(1%)

1K

1K

HOR

GND

10K

1u

1000p

24K

24K

0.47u

0.01u

16p

10u

SVO

V/C

GND

1u

[Y-IN ]

EXT-V IN

EXT-AUDIO

0.01u

47u

[S-C IN]

INT-V IN

15uH

1K

VCO

1000p

IN

10p

1u

680K

330

2.2u

1K

0.47u

COIL

0.47u

330

10u

3K

0.01

1000p

FBP

C/D

VCO

29 28

32 31 30

XRAY

36 35 34 33

APC1

VCO

39 38

40 37

43 42 41

44

CLAMP CLAMP

46 45

48 47

50

52 51 49

53

54

HOR

ACC

KILLER

TINT

BPF

(ON/OFF)

SW

SW

VIDEO

AFT

A2C PLL

AMP

VIDEO

SPLL

BPF

BPF

HOR

1/256

COLOR

CLAMP

DEMO

SYNC

TRAP

TRAP

LIM

AMP

BRIGHT

CONTRAST

BLACK

SEP

PEAKING

DELAYLINE

DET

VIDEO

AFC2

PHASE

AFC1

VER

RGB

STRETCH

CORING

FM

DET

VER

SEP

OSD

MATRIX

OSD

CONTRAST

VIF

IF

AGC

SW

HOR

OUT

SHIFTER

Vcc

HOR

C/D

VER

RAMP

SW

DRIVE/CUTOFF

BRIGHT

CLAMP

ABL

BUS

5V

IF Vcc

RF

AGC

DC

VOL

OUT

HOR

1u

3K

0.01u

10u

56p

100

Vcc

0.01u

10u

0.1u( )

0.1u( )

0.1u( )

1K

1K

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

100K

0.01u

5 6 7 8 9

0.01u

0.022u( )

0.01u( )

1 2 3 4

VC

AUDIO

0.015u

150

0.33u( ) 0.33u( )

VER

5.6k

B

G

R

100

100

0.1u

100K

1u

100

SAW

FILTER

30K

OUTP

150

OUT

OUT

OUT

OUT

IF

HOR

VCC(9V)

Out

Sync

VCC

(9 12V)

IN

FB

B

IN

G

IN

R

IN

LA76814K BLOCK DIAGRAM

ABL

BUS

CLOCK

BUS

DATA

AF

VCC

IF IN

RF

-5-

IC Block Diagram

IC301<Vertical Output> LA7840

THERMAL
PROTECTION

PUMP
UP

-

AMP

+

1

2

GND

Ver.OUTPUT

IC 403(3W AUDIO OUTPUT)LA 4285

3

OUTPUT STAGE Vcc

EVR

4

5

NON INV.INPUT

INVERTINO INPUT

7

6

c
c
V

PUMP UP OUT

+

-

INT

EXT

1 2 6543 1097 8

5V

++6++

++++

PRE

GND

INT/EXT
SM

EVR
CONT

-6-

D.C.

PWR
NF

PWR
GND

VCC

++

+

+

RL 8

IC Block Diagram

IC602<POWER > STR-G6653

VIN

4

1

D

START

REG.

T.S.D

O.V.P

LATCH

O.S.C

+

Comp2

Comp2

DRIVE

2

-

Vth(1)

+

Comp1

-

Vth(2)

S

5

O.C.P/F.B

3

GND

IC603<PHOTO TRANSISTOR> TLP621

TLP621

1

2

1:ANODE
2:CATHODE
3:EMITTER
4:COLLECTOT

4

3

-7-

MAIN PCB Top Layer

-8-

CRT, FRONT AV&CONTROL PCB Top Layer

FRONT AV & CONTROL PCB TOP LAYER

-9-

Service Adjustments

Please notice the following before alignment and equipment

1. Don’t short any two soldering points, which should not be shorted and don’t touch any components,
which should not be touched.

2. Please pull out plug before equipment.

3. For safety reasons, all components equipped or replaced should be identical with BOM.

4. Must be warm up for 30 minutes or more and degauss CRT thoroughly with demagnetizer before
alignment.

The data of EEPROM must be stored before the adjustment for main chassis. And EEPROM must be
corrected by the correct file “3Y03_ROM_CORRECT.hex” to avoid signal of CH6 weaken. R.bias,

G.bias, B.bias, R.drv, G.drv, B.drv should be set to proper values. Sub_bright is set to 63 usually.

Tools and equipments for adjustment

1. small “-“ screwdriver

2. screwdriver without inductance

3. Pattern Generator

4. DC Regulated power supply

5. Digital Voltmeter

6. Sweep Signal Generator

7. 20MHz 2-channel Oscilloscope

Signal condition

ITEMS LOGO

PICTURE
CARRIER

PATTER N SYSTEM

SOUND

MODE

REMARK

1 CH14 471.25 MHZ COLOR BAR NTSC/M

MONO

1KHz

2 CH3 61.25 MHz GRAY SCALE NTSC/M

BTSC

0.3k,3kHz

3 CH8 181.25 MHz MONOSCOPE NTSC/M

MONO
MUSIC

4 CH12 205.25 MHz

CROSS HATCH

NTSC/M

MONO

1KHz

Adjust for main chassis

PIF Adjustment (45.75MHz)

a. Tuner AGC connects to GND. Pattern Generator outputs 45.75MHz I.F. signal (70dbµV)and connects to SAW filter

output terminal through a capacitor .
b. Connect Digital voltmeter across C227. DC Regulated power supply positive terminal output +14V to C617.
c. Adjust L203 coil to obtain 3.6V Digital voltage meter reading.

NOTE: To cancel this adjustment , L203 can be adjusted before inserted to the chassis with a special equipment.

-10-

Service Adjustments

B+ adjustment

a. Disconnect horizontal load. Connect a bulb (100 W) AC 250V across C321.
b. Add 220V AC 50HZ to CN601 and switch on power switch.
c. Test the voltage with digital voltage meter between C321 two terminals.
d. Adjust VR601 to obtain +110V¡À0.5V.

AGC alignment

a. Receive 60dB RF signal. Connect Digital voltmeter positive terminal to tuner AGC terminal and negative terminal

to GND.

b. Press “MENU” key, then press “Q.VIEW” key, “MUTE” key in turn on telecontroller. TV SET will go to factory mode.

Press “TIMER” key to go to the next factory menu. Go to MENU5 status by this means. Press “MENU” key to exit
factory mode.

c. Select RF.AGC by pressing “CH+” and “CH-“keys. Adjust “VOL+” and “VOL-“ keys to obtain 4V Digital voltage

meter reading.

COMPLETE MACHINE GENERAL ADJUSTMENT

Go to factory mode according to 4-2-2 before warm up line
Focus Adjustment

a. Receive monoscope pattern.

b. Set TV to work in dynamic status.

c. Adjust the focus knob of FBT to get the clearest picture.

Screen Voltage Adjustment

a. Check the R.bias, G.bias, B.bias, R.drv, G.drv, B.drv and sub_bright. Go to factory mode “MENU2” status

according to 4-2-2. Usually G.bias should be same as the value of auto white balance equipment. And

SUB_BRIGHT is 63.
b. Set Cross_BW ‘3”. Then the picture will be a white “+”. Cross_BW is in factory menu 3.
c. In menu 5, select SUBB.ADJ and set it to “1”. Adjust the screen knob of FBT to get a faintness “+”.

d. Restore the SUBB.ADJ to “0” and CROSS.BW to “0”.

White Balance Adjustment (Applied in factory)

a. Set TV AV status in custom mode(Or other mode need for the adjustment) . Receive black white pattern.

b. Insert six-row-wire into CN002.Press adjustment keys, and then go to automatic white balance adjustment.
c. PIN DISCRIPTIONN OF CN002:

1£ºSDA£¬ 2£ºSCL£¬ 3£ºGND£¬ 4£ºGND£¬ 5£ºSCL£¬ 6£ºSDA¡£

d. After adjusting well, pull out six-row-wire.

-11-