Fisher PC-R20R2 User manual

SERVICE MANUAL Colour Television
FILE NO.
Model No.PC-R20R2
(USA)
Service Ref.No.PC-R20R2-00
SPECIFICATIONS
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.
Design and specifications are subject to change without prior notice.
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
REFERENCE NO. SM 2300011
: M
:
: 20 inch screen
: 75 Ohm Coaxial Cable
:
: (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
NTSC
Audio/Video -In/Out
x20.1(D) x 18.3(H)inch
(W) x 7.9(L) x 0.9(D)inch

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
-2-
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 exce-
eds 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 shouldbe considered whena component replacementis 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 onlyparts designated onthe parts listin this manual be usedfor com-
ponent replacement designated bymark . No deviations fromresistance wattageor vol-
tage ratings maybe made forreplacement items designated bymark .
!
!
!

LA76814/76810
LC863224A-5V23
TUNER SAW.FIL
PRE.AMP
R G B Y
La4285
EEPROM SDA/SCL
22-25
14-17
RGB AMP CRT
La7840
V-OUT H-OUT
H-FBP
FBP
TV-AUDIO
AV1/AV2 AUDIOIN
VIDEO-IN
VIDEO-OUT
HEF4O52BP
HEF4O53BP
POWER
110V (B+) 21V 5V 9V
19-21
24V
9V/12V
V.SYN H.SYN
SDA
SCL
RF-AGC
AFC
VIDEO
11 12 41 40
23
28 27
40 10
29
30
21 20 19 14
SPEAKER-L SPEAKER-R
I c401
AV1/AV2
VIDEOIN
Ic400
IC403
I c301
I c201
Ic001
Ic002
VERTICAL
DEFLECTION
HORIZONTAL
DEFECTION
FOUCS
SCREEN
27 28
4 5 6 2
Chassis Block Diagram
-3-

IC Block Diagram
-4-
IC 001 (MULTI SYSTEM COLOR TV CPU) LC863224A

IC Block Diagram
-5-
IC 201 (IIC BUS SINGLE CHIP VIF,SIF,VIDEO CHROMA) LA76814K
LA76814K BLOCKDIAGRAM
FBP
IN
REF
HOR
GND
V/C
GND
EXT-V IN
[Y-IN ]
INT-V IN
[S-C IN]
V/C
VCC
VCO
COIL
EXT-AUDIO
IN SVO
10p
330
0.47u
10u
10K
7.5K
330p
4.7K
MetalFilm(1%)
0.47u
3K 0.01
24K
24K
0.47u
0.01u
16p
1u
10K
680K
2.2u
1u
1u
1K
1K
1000p
1000p
54 50
53 52 51 49 48 47 46 45 44 43 42 41 40 37 36 35 34 33 32 31 30 29 28
39 38
10u
330
1000p
1K
15uH
1K
0.01u
47u
VC
SAW
FILTER
AUDIO OUTP
RF
IF IN
IF
VCC
AF
ABL R
IN
G
IN
B
IN
FB
IN VCC
(9 12V)
R
OUT
G
OUT
B
OUT
VER
OUT
HOR
VCC(9V)
HOR
OUT
0.01u( )
0.022u( )
30K
0.01u
100 1u
100K100K
1K
1K
100
100
BUS
DATA
BUS
CLOCK
0.33u( )0.33u( )
10u
0.01u
0.015u
3K 1u
150
0.1u( )
150
10u
10 1112 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
1 2 3 4 5 6 7 8 9
100
Sync
Out
0.1u
0.01u
0.1u( )
0.1u( )
56p
0.01u
5.6k
Vcc
BPF
SPLL
BPF FM
DET
SW
DC
VOL
IF
AGC
RF
AGC
VIDEO
DET
TRAP
VIDEO
AMP
A2C PLL
LIM AMP
VIF
IF Vcc
5V
AFT
BUS ABL CLAMP
OSD
CONTRAST
BRIGHT
CLAMP CLAMP
VIDEO
SW
TRAP
DELAYLINE
PEAKING CORING
BLACK
STRETCH
SYNC
SEP
SW
DRIVE/CUTOFF
OSD
SW
FBP
HOR
VCO
1/256
HOR
C/D
AFC1
AFC2
PHASE
SHIFTER
HOR OUT
HOR
Vcc
VER
RAMP
VER C/D
VER SEP
RGB
MATRIX
CONTRAST
BRIGHT
BPF
(ON/OFF)
DEMO
COLOR CLAMP
VCO
TINT
APC1
ACC
KILLER
XRAY

IC Block Diagram
-6-
IC301<Vertical Output> LA7840
7
6
5
4
3
2
1
GND
Ver.OUTPUT
OUTPUT STAGE Vcc
NON INV.INPUT
INVERTINO INPUT
Vcc
PUMP UP OUT
PUMP
UP
AMP
THERMAL
PROTECTION
-
+
IC 403(3W AUDIO OUTPUT)LA 4285
+
12654310978VCC
INT
+
EXT
PRE
GND
INT/EXT
SM
EVR
CONT
++
6
++
D.C.
++++
PWR
NF
PWR
GND
++
RL 8
+
-
EVR
5V

IC Block Diagram
-7-
IC602<POWER > STR-G6653
Comp2
Vth(2)
Vth(1)
Comp1
GND
O.C.P/F.B
DRIVE
LATCH
O.V.P
REG.
T.S.D
VIN
4
START
O.S.C
-
+
-
+
5
2
S
1
D
3
Comp2
IC603<PHOTO TRANSISTOR> TLP621
TLP621
1
23
4
1:ANODE
2:CATHODE
3:EMITTER
4:COLLECTOT

MAIN PCB Top Layer
-8-

CRT, FRONT AV&CONTROL PCB Top Layer
FRONT AV & CONTROL PCB TOP LAYER
-9-

Service Adjustments
-10-
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
1CH14 471.25 MHZ COLOR BAR NTSC/M MONO
1KHz
2CH3 61.25 MHz GRAY SCALE NTSC/M BTSC
0.3k,3kHz
3CH8 181.25 MHz MONOSCOPE NTSC/M MONO
MUSIC
4CH12 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.

Service Adjustments
-11-
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.

Ver tical size and pincushion adjustment
Service Adjustments
-12-
White balance adjustment (Applied when servicing)
a. Set TV AV status and receive GREY SCAL.
b. The one sampling tube of CRT color analyzer (CA-100) covers on GREY signal and
the another covers on white signal.
c. Go to factory mode “MENU2”. Obtain GREY signal X=281 and y=311 by adjusting R-CUT and B-cut. Obtain white
signal X=281 and y=311 by adjusting R-DRV and B-DRV. Obtain both X=281 and Y=311 by adjusting the two
status repeatedly.
Sub_bright adjustment
Receive the gray scale . Get into the menu5 of factory mode. Set SUBB.ADJ to “1”. Then adjust the SUB..BRI
option to get a scale to be seen a little brightness(Only two rows can be seen).
Vertical Size and PinCushion Adjustment
a. Receive monoscope pattern. Set TV standard status. Adjust V.size to obtain picture’s vertical redisplay ratio more
than 90% in factory mode “MENU1”.
b. Receive cross hatch pattern. Set TV standard status. Adjust V.LINE and V.SC to obtain picture’s vertical pin
cushion a good status in factory mode “MENU1”.
c. Receive cross hatch pattern. Set TV standard status. In factory mode “MENU1” adjust V.POS to obtain picture’s
vertical center at the center of CRT screen.
Horizontal Center Adjustment and horizontal position of OSD adjustment
a. Receive monoscope PATTERN. Set TV standard status. Adjust H.PHASE in menu 1 to obtain horizontal center
at the center of CRT screen.
b. Adjust the “OSD.HPOS” to get right display position.
SUB.TINT ADJUSTMENT
Receive the color bar signal of NTSC system. Set the picture mode at normal mode. Adjust the ‘SUB.TINT’option
in menu5 at sevice mode to get the right hue .
MTS ADJUSTMENT
Receive the RF CROSS-TALK signals , but FM with BTSC .Enter into the factory mode. Set ADJ.FREQ to 1 in
“9852 AUTO.ADJ”. Wait 1 second . Quit factory menu after “ADJUSTING ” change to “0”.

COLOR PURITY ADJUSTMENT
a. Before color purity adjustment, Warm up the TV set over 15 minutes and fully degauss.
b. Receive pure white signal in AV status and set the TV receiver dynamic.
c. Go to factory mode “MENU2”. After write down the values of R-BIAS and B-BIAS, set the values of R-BIAS and
B-BIAS zero.
d. Loosen the clamp screw of the deflection yoke and pull the deflection yoke towards color purity magnetic loop.
e. Adjust color purity magnetic loop to make the green area at the center of CRT screen.
f. Slowly push the deflection yoke toward the front of CRT and set it where a uniform green field is obtained.
Tighten the clamp screw of the deflection yoke.
g. Restore the values of R-BIAS, G-BIAS and B-BIAS.
CONVERGENCE ADJUSTMENT
a. Receive a dotted pattern. Set the TV receiver dynamic.
b. Loose the convergence magnet clamper and align red with blue dots at the center of the screen by rotating (R, B)
static convergence magnets.
c. Align Red/Blue with green dots at the center of the screen by rotating (RB-G) static convergence magnet.
d. Remove the DY wedges and slightly tilt the deflection yoke horizontally and vertically to obtain the good overall
convergence. Fix them after the good overall convergence got.
e. Fix the convergence magnets by turning the clamper.
f. If purity error is found, follow “PURITY ADJUSTMENT” instructions.
Purity Magnet
RB-G RB
Magnet Clamper
Static Magnet
Ver tical size and pincushion adjustment
Service Adjustments
-13-

Ver tical size and pincushion adjustment
Service Adjustments
APPENDIX
FACTORY MENU DISCRIPTION
MENU1 VAL UE DISCRIPTION
1V.SIZE 101 Align vertical amplitude
2V.POS 32 Align vertical DC bias
3V.LINE 16 Align vertical linearity
4V.S C 0Align vertical S-correction
5H.PHASE 8Align sync to flyback phase
6H.BLK.RL 4H-blanking Control(Width /Phase)
7H.FREQ 22 Align ES Sample horizontal frequency
MENU2
1V.KILL 0Disable vertical output
2R.B 138 Align Red out DC level
3G.B 182 Align Green out DC level
4B.B 148 Align Blue out DC level
5R.D 67 Align Red out AC level
6G.D 8Align Green out AC level
7B.D 45 Align Blue out AC level
MENU3
1RG.GAM 1Disable R/G gamma correction (0/ON; 1/OFF)
2B.GAM 3Select and Disable B gamma correction(0~2/ON;3/OFF)
3R.B.ANG 1Adjust the demodulation angle of R-Y and B-Y
4AT.FLESH 0
5GRAY.MODE 0Select Test mode (0/White; 1/Gray)
6CROSS.BW 0Service Test mode (0/TV; 1/Black; 2/White; 3/Crosshatch)
7AFC.GAIN 0Select Horiz. 1st loop gain & H-sync gate on/off(0/auto;1/enforce)
8H.BLK.SW 0H BLK R&L selection(0/right side blanking can be adjusted;1/left)
MENU4
1FILT.SYS 1Select Y/C filter mode(0,2/3.58 unsymm.; 1,3/3.58 sym.; 4~7/no filt)
2CORING 1Enable Luminance coring( 0/Off; 1/ON)
3OSD.CONT 1
4OSD.HPOS 30 Align the horizontal position of OSD
5BLK.STR.D 0Disable black stretch
6BRIABL.T 0Align brightness ABL threshold
MENU5
1RF.AGC 31 Align RF AGC threshold
-14-

Ver tical size and pincushion adjustment
Service Adjustments
-15-
OPTION
12 AV.CH 3Select AV numbers(0/ No AV;1/1 AV; 2,3/2AV)
2SRH.SPEED 0Select auto search speed(0/fastest, 7/lowest)
3TDA9852 1Disable 9852(0/disable; 1/able)
4TUN.AS.V 1Select the Tuner address(0/Tuner pin3 to ground;1/pin3 not used)
9852 AUTO.ADJ
1ADJ.FREQ 0Disable auto adjusting(0/disable; 1/get into autoadjust mode)
2ADJUSTING 0
3FM.LVL 16
476075.VOL 0
5L3-L0 0input level adjust
6TC2-TC0 0timing current alignment data
7A14-A10 0stereo alignment data for wideband expander
8A24-A20 0stereo alignment data for spectral expander
TDA1
1VOL.RIGHT 125 volume control right
2VOL.LEFT 125 volume control left
3GMU 0mute control for all outputs (general mute )
4AVL ON 0auto volume control (with 0.1Vrms-1.1Vrms input to get constant output
0.2Vrms)
5LOFF 0switch loudness on/off
6CCD 0
7SC2-SC0 2selection between line in and line out
8SAP.ID 0
TDA2
1STERO.ID 1
2TZCM 0zero cross mode in volume operation
3LMU 0mute control for line out
4EF2-EF0 0selection between mono, stereo linear, spatial stereo and pseudo mode
5L3-L0 0input level adjust
6A14-A10 0stereo alignment data for wideband expander
7A24-A20 0stereo alignment data for spectral expander
8STS 0stereo level switch

-16-
White Balance address
White Balance address
Data Name E2PROM Address LA76814 ADDRESS
#1011 1010B
bright 12H #0001 0100B
contrast 11H #0001 0101B
color 10H #1011 1010B
Sub-bright 24H #0001 0011B
R.B 1EH #0000 1101B
G.B 1FH #0000 1110B
B.B 20H #0000 1111B
R.D 21H #0001 0000B
G.D 22H #0001 0000B
B.D 23H #0001 0010B
TDA3
1ADJ 0stereo adjust on/off
2AT1-AT2 0attack time at AVL
3TC2-TC0 0timing current alignment data
4WR.ERR 0
5RD ERR 0
6MANU ADJ 0
7STEREO 0mode selection for line out
8SAP 0mode selection for line out
Ver tical size and pincushion adjustment
Service Adjustments

COLOR PURITY ADJUSTMENT
(1) Before color purity adjustment,warm up the TV set over 15 minutes and fully degauss.
(2) Receive pure white signal in AV status and set the TV receiver dynamic.
(3) Go to factory mod MENU2. After write down the values of R-BIAS and B-BIAS, set the values of R-
BIAS and B-BIAS zero.
(4) Loosen the clamp screw of the deflection yoke and pull the deflection yoke towards color purity
Magnetic loop.
(5) Adjust color purity magnetic loop to make the green area at the center of CRT screen.
(6) Slowly push the deflection yoke toward the front of CRT and set it where a uniform green field is
Obtained. Tighten the clamp screw of the deflection yoke.
(7) Restore the values of R-BIAS,G-BIAS AND B-BIAS.
CONVERGENCE ADJUSTMENT
(1) Receive a dotted pattern. Set the TV receiver dynamic.
(2) Loose the convergence magnet clamperrrrr and align red with blu dots at the center of the screen by
rotating(R,B) static convergence magnets.
(3) Align Red/Blue with green dots at the center of the screen by rotating(RB-G) static convergence
magnet.
(4) Remove the DY wedges and slightly tilt the deflection yoke horizontally and vertically to obtain the
good
Purity Magnet
RB-G RB
Magnet Clamper
Static Magnet
Purity and Convergence Adjustment
-17-

Control Location
-18-
1. Remote Sensor
2. Power Indicator
3. Main Switch
4. Speakers
5. Program Down & Up Button
6. Volume Down & Up Button
7. Menu Button
8. AV/TV Button
9. Front AV In (Option)
10. Audio/Video - In/Out Jack
11. AC Power Cord
12. Terminal Antenna (75 Ohm)
3
21 5 86 74 9 4
10
12
11
(STEREO)
(MONO)

Input and Output Terminals
-19-
VIDEO AND AUDIO INPUT/OUTPUT TERMINALS
1. Video / Audio input for playback for VCR.
2. Video / Audio output for TV monitor output.
*Please keep AC cord unplugged when connecting TV system.
RR
LL
VIDEOVIDEO AUDIOAUDIO
AV-IN
AV-OUT
NOTE:
This is a mono CTV even though there are R & L audio input & output jack. These
audio R/L input terminals are parallel connected inside and make mixed monaural
sound output .There are same monaural audio output come from R/L output terminals.
OUT IN
VIDEO VIDEOAUDIO AUDIO
(STEREO)
(MONO)

Operation Instructions
-20-
Video Menu Time Menu Setup Menu Exit Menu
1.Enter the video menu , you can select the picture quality instantly among four
preset modes and one user-set mode.
(User-set mode)
Custom Standard Sports Movies Mild
*You can adjust CONTRAST,BRIGHT , SHARPNESS , COLOR and TINT items
by pressing the VOL. +/- buttons . The adjusted level is stored in Custom mode.
Turn the TV set on, then power indicator will light up. After a few seconds , the currently program number is
displayed on the top right -hand corner of the screen.
MENU BUTTON
1.Press this button to select menu. VIDEO, TIME, and SETUP menu can be selected cyclically.
2.After enters each menu, you can select the desired adjusting item by the PROG.+/- buttons, and adjust the
item by the VOL. +/- buttons.
*When you select a item, symbols¡° / ¡±will display both sides of the item.
Video menu
Video
Time
Setup
Custom
Contrast
Bright
Sharpness
Color
Tint
16
16
16
16
-15
Video
Time
Setup
Clock
Timer
TV On
TV Off
Off
--:--
--:--
--:--
Time menu
Video
ST
SAP
Mono
On
Audio menu(option)
1.ST:
Press the VOL.+/-buttons can select the stereo mode , the order shown below:
Mono Spatial Linear Psuedo
2.SAP:
You can adjust the SAP ON to SAP OFF by the VOL+/-buttons ,.
You can use the Second Audio Program when you select the SAP ON .
3.BALANCE:
Press the VOL+/-buttons can adjust the left or right volume balance .
* The MTS/SAP function is only an option for some models.
Audio
Time
Setup
Balance 00
Audio Menu
Audio
Audio
(Option)
1.CLOCK:
Press the VOL.- button to set hour, and the VOL.+ button set minute .
2.TIMER£º
When you select the "Timer ON" mode, you can set the time of TV ON or TV
OFF.
*TV On: The TV will automatically turn on at the preset time.
TV Off: The TV will automatically turn off at the preset time.