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SERVICE MANUAL
BA-4D CHASSIS
MODEL
COMMANDER
DEST
CHASSIS NO.
KV-20M42
RM-Y156
US
SCC-S27A-A
KV-20M42
RM-Y156
CND
SCC-S28B-A
KV-20S42
RM-Y155
US
SCC-S27B-A
KV-20S42
RM-Y155
CND
SCC-S28C-A
KV-20S43
RM-Y156W
US
SCC-S27C-A
KV-20S43
RM-Y156W
CND
SCC-S28D-A
KV-21MB42C
RM-Y156
E
SCC-S25E-A
KV-21MB42M
RM-Y156
MX
SCC-S26A-A
KV-21MB42P
RM-Y156
E
SCC-S25A-A
KV-21ME42
RM-Y156
E
SCC-S25B-A
KV-21ME42C
RM-Y156
E
SCC-S25F-A
KV-21SB42C
RM-Y155
E
SCC-S25G-A
KV-21SB42M
RM-Y155
MX
SCC-S26B-A
KV-21SE42
RM-Y155
E
SCC-S25D-A
KV-21SE42C
RM-Y155
E
SCC-S25H-A
KV-21SE82
RM-Y165
E
SCC-S25J-A
KV-21SE82C
RM-Y165
E
SCC-S25K-A
MICROFILM
TRINITRON® COLOR TV
RM-Y155
KV-21SE82


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SPECIFICATIONS
Design and specifications are subject to change without notice.
(
·)SRS (SOUND RETRIEVAL SYSTEM)
The (
·)SRS (SOUND RETRIEVAL SYSTEM) is
manufactured by Sony Corporation under license
from SRS Labs, Inc. It is covered by U.S. Patent No.
4,748,669. Other U.S. and foreign patents pending.
The word `SRS' and the SRS symbol (
·) are
registered trademarks of SRS Labs, Inc.
BBE and BBE symbol are trademarks of BBE
Sound, Inc. and are licensed by BBE Sound, Inc.
under U.S. Patent No. 4,638,258 and 4,482,866.
KV-20M42
KV-21MB42C,
KV-21MB42M,
KV-21MB42P
KV-21ME42,
KV-21ME42C
KV-20S42,
KV-20S43
KV-21SB42C,
KV-21SB42M
KV-21SE42,
KV-21SE42C
KV-21SE82,
KV-21SE82C
Power Requirements
120V 60Hz
AUTO VOLT
120-220V,
50/60 Hz
AUTO VOLT
120-220V,
50/60 Hz
120V 60 Hz
AUTO VOLT
120-220V,
50/60 Hz
AUTO VOLT
120-220V,
50/60 Hz
AUTO VOLT
120-220V,
50/60 Hz
Number of inputs/outputs
Video 1)
2222222
Audio Input 2)
2222222
Audio Out 3)
------
1
Speaker Output (W)
3W
3W
3Wx2
3W x 2
3Wx2
4Wx2
5Wx2
Power Consumption (W)
In Use (Max)
80W
80W
80W
90W
90W
90W
90W
In Standby
1W
1W
1W
1W
1W
1W
1W
Dimensions (W/H/D)
(mm)
522 x 477 x 479
mm
522 x 477 x 479
mm
522 x 477 x 479
mm
522 x 477 x 479
mm
522 x 477 x 479
mm
522 x 477 x 479
mm
522 x 477 x 479
mm
(in)
205/8 x 18
13/
16 x
187/8 in.
205/8 x 18
13/
16 x
187/8 in.
205/8 x 18
13/
16 x
187/8 in.
205/8 x 18
13/
16 x
187/8 in.
205/8 x 18
13/
16 x
187/8 in.
205/8 x 18
13/
16 x
187/8 in.
205/8 x 18
13/
16 x
187/8 in.
Mass
(kg)
21.6 kg
21.6 kg
21.6 kg
21.6 kg
21.6 kg
21.6 kg
21.6 kg
(lbs)
48 lbs.
48 lbs.
48 lbs.
48 lbs.
48 lbs.
48 lbs.
48 lbs.
1) 1 Vp-p 75 ohms unbalanced, sync negative
2 ) 500 mVrms (100% modulation), impedance: 47 kilohms
3) More than 408 mVrms at the maximum volume setting (variable)
More than 408 mVrms (fix), Impedance: 5 kilohms
-- 2 --
KV-20M42/20S42/20S43/21MB42C/21MB42M/21MB42P/21ME42/21ME42C/
21SB42C/21SB42M/21SE42/21SE42C/21SE82/21SE82C
Television system
American TV standard/NTSC
Picture tube
Trinitron® Tube
Channel coverage
VHF:2-13/UHF:14-69/CATV:1-125
Visible screen size
20" picture measured diagonally
Actual screen size
21" picture measured diagonally
Antenna
75 ohm external terminal for VHF/UHF
Supplied Accessories
Remote Commander (RM-Y155)
(KV-20S42/21SB42M/42C/21SE42/42C)
Remote Commander (RM-Y156)
(KV-20M42/21MB42C/42M/42P/21ME42/42C)
Remote Commander (RM-Y156W)
(KV-20S43)
Remote Commander (RM-Y165)
(KV-21SE82/82C)
Size AA (R6) batteries (2)
Optional Accessories
Dipole antenna
Connecting cables VMC-810S/820S, VMC-720M,
YC-15V/30V, RK74A
U/V mixer EAC-66


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Section
Title
Page
Warnings and Cautions .................................................................................................................................................. 4
Self-Diagnostic Function ................................................................................................................................................. 4
Safety Check Out Instructions ........................................................................................................................................ 7
1.
GENERAL ............................................................................................................................................................ 8
2.
DISASSEMBLY
2-1.
Rear Cover Removal .................................................................................................................................................... 12
2-2.
A Board Removal .......................................................................................................................................................... 12
2-3.
Service Position ............................................................................................................................................................ 12
2-4.
Picture Tube Removal .................................................................................................................................................. 13
3.
SET-UP ADJUSTMENTS
3-1.
Beam Landing ............................................................................................................................................................... 14
3-2.
Convergence ................................................................................................................................................................. 15
3-3.
Focus ............................................................................................................................................................................ 16
3-4.
Screen (G2) ................................................................................................................................................................... 16
3-5.
Method of Setting the Service Adjustment Mode .............................................................................. ........................... 16
3-6.
White Balance Adjustments .......................................................................................................................................... 16
4.
SAFETY RELATED ADJUSTMENTS
4-1.
R582 Confirmation Method (HV Hold-Down Confirmation and Readjustments) .................................................... 17
4-2.
B+ Voltage Confirmation and Adjustment .................................................................................................................... 17
5.
CIRCUIT ADJUSTMENTS
5-1.
Setting the Service Adjustment Mode .......................................................................................................................... 19
5-2.
Memory Write Confirmation Method ............................................................................................................................. 19
5-3.
Adjust Buttons and Indicators ....................................................................................................................................... 19
5-4.
A Board Adjustments .................................................................................................................................................... 22
6.
DIAGRAMS
6-1.
Block Diagram ............................................................................................................................................................... 27
6-2.
Circuit Board Location .................................................................................................................................................. 30
6-3.
Printed Wiring Boards and Schematic Diagrams ......................................................................................................... 33
·
A Board ..................................................................................................................................................................... 33
·
C Board .................................................................................................................................................................... 42
6-4.
Semiconductors ............................................................................................................................................................ 43
7.
EXPLODED VIEWS
7-1.
Chassis (KV-20S43/21SE42/42C/82/82C/ME42/42C) ................................................................................................. 44
7-2.
Chassis (KV-20M42/S42/21MB42C/42M/42P/SB42C/42M) ........................................................................................ 45
8.
ELECTRICAL PARTS LIST ...........................................................................................................................47
Table of Contents for Parts List ...........................................................................................................................................47
A Board Common Parts Listing............................................................................................................................................48
C Board Parts List................................................................................................................................................................56
A Board Variant Parts Lists...................................................................................................................................................57
Packaging List and Accessories....................................................................................................................................................65
TABLE OF CONTENTS
-- 3 --
KV-20M42/20S42/20S43/21MB42C/21MB42M/21MB42P/21ME42/21ME42C/
21SB42C/21SB42M/21SE42/21SE42C/21SE82/21SE82C


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-- 4 --
KV-20M42/20S42/20S43/21MB42C/21MB42M/21MB42P/21ME42/21ME42C/
21SB42C/21SB42M/21SE42/21SE42C/21SE82/21SE82C
WARNINGS AND CAUTIONS
CAUTION
SHORT CIRCUIT THE ANODE OF THE PICTURE TUBE AND
THE ANODE CAP TO THE METAL CHASSIS, CRT SHIELD, OR
CARBON PAINTED ON THE CRT, AFTER REMOVING THE
ANODE.
WARNING!!
AN ISOLATION TRANSFORMER SHOULD BE USED DURING
ANY SERVICE TO AVOID POSSIBLE SHOCK HAZARD,
BECAUSE OF LIVE CHASSIS. THE CHASSIS OF THIS
RECEIVER IS DIRECTLY CONNECTED TO THE AC POWER
LINE.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK
ON
THE SCHEMATIC DIAGRAMS, EXPLODED VIEWS, AND IN THE
PARTS LIST ARE CRITICAL FOR SAFE OPERATION. REPLACE
THESE COMPONENTS WITH SONY PARTS WHOSE PART
NUMBERS
APPEAR
AS
SHOWN
IN
THIS
MANUAL
OR IN SUPPLEMENTS PUBLISHED BY SONY. CIRCUIT
ADJUSTMENTS THAT ARE CRITICAL FOR SAFE OPERATION
ARE IDENTIFIED IN THIS MANUAL. FOLLOW THESE
PROCEDURES WHENEVER CRITICAL COMPONENTS ARE
REPLACED OR IMPROPER OPERATION IS SUSPECTED.
ATTENTION
APRES AVOIR DECONNECTE LE CAP DE L'ANODE, COURT-CIRCUITER L'ANODE
DU TUBE CATHODIQUE ET CELUI DE L'ANODE DU CAP AU CHASSIS
METALLIQUE DE L'APPAREIL, OU AU COUCHE DE CARBONE PEINTE SUR LE
TUBE CATHODIQUE OU AU BLINDAGE DU TUBE CATHODIQUE.
ATTENTION!!
AFIN D'EVITER TOUT RESQUE D'ELECTROCUTION PROVENANT D'UN CHÁSSIS
SOUS TENSION, UN TRANSFORMATEUR D'ISOLEMENT DOIT ETRE UTILISÉ
LORS DE TOUT DÉPANNAGE. LE CHÁSSIS DE CE RÉCEPTEUR EST
DIRECTEMENT RACCORDÉ À L'ALIMENTATION SECTEUR.
ATTENTION AUX COMPOSANTS RELATIFS A LA SECURITE!!
LES COMPOSANTS IDENTIFIES PAR UNE TRAME ET PAR UNE MARQUE
SUR
LES SCHEMAS DE PRINCIPE, LES VUES EXPLOSEES ET LES LISTES DE
PIECES SONT D'UNEIMPORTANCE CRITIQUE POUR LA SECURITE DU
FONCTIONNEMENT. NE LES REMPLACER QUE PAR DES COMPOSANTS SONY
DONT LE NUMERO DE PIECE EST INDIQUE DANS LE PRESENT MANUEL OU
DANS DES SUPPLEMENTS PUBLIES PAR SONY. LES REGLAGES DE
CIRCUIT DONT L'IMPORTANCE EST CRITIQUE POUR LA SECURITE DU
FONCTIONNEMENT SONT IDENTIFIES DANS LE PRESENT MANUEL. SUIVRE CES
PROCEDURES LORS DE CHAQUE REMPLACEMENT DE COMPOSANTS
CRITIQUES, OU LORSQU'UN MAUVAIS FONTIONNEMENT SUSPECTE.
SELF-DIAGNOSTIC FUNCTION
The units in this manual contain a self-diagnostic function. If an error occurs, the STANDBY/TIMER LED will automatically begin to
flash. The number of times the LED flashes translates to a probable source of the problem. A definition of the STANDBY/TIMER LED
flash indicators is listed in the instruction manual for the user's knowledge and reference. If an error symptom cannot be reproduced, the
Remote Commander can be used to review the failure occurrence data stored in memory to reveal past problems and how often these
problems occur.
Diagnostic Test Indicators
When an error occurs, the STANDBY/TIMER LED will flash a set number of times to indicate the possible cause of the problem. If
there is more than one error, the LED will identify the first of the problem areas.
Results for all of the following diagnostic items are displayed on screen. No error has occurred if the screen displays a "0".
Diagnostic Item
Description
No. of Times
STANDBY/TIMER
LED Flashes
Self-diagnostic Display/
Diagnostic Result
Probable Cause
Location
Detected Symptoms
Power does not turn on
Does not light
· Power cord is not plugged in.
· Fuse is burned out (F601).
· Power does not come on.
· No power is supplied to the TV.
· AC power supply is faulty.
+B overcurrent (OCP)*
2 times
2:0 or 2:1
· H.OUT (Q502) is shorted (A Board)
· IC701 and Q701 (C Board) are shorted.
· Power does not come on.
· Load on power line is shorted.
Vertical deflection stopped*
4 times
4:0 or 4:1
· +13V is not supplied. (A Board)
· IC541 is faulty. (A Board)
· Has entered standby state after horizontal raster.
· Vertical deflection pulse is stopped.
· Power line is shorted or power supply is stopped.
White balance failure
(not balanced)
5 times
5:0 or 5:1
· Video OUT (Q394 to 392) is faulty. (A Board)
· IC301 is faulty. (A Board)
· Screen (G2) is improperly adjusted.**
· No raster is generated.
· CRT cathode current detection reference
pulse output is small.
* If a +B overcurrent is detected, stoppage of the vertical deflection is detected simultaneously.
The symptom that is diagnosed first by the microcontroller is displayed on the screen.
** Refer to Screen (G2) Adjustments in Sections 3 and 4 of this manual.


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-- 5 --
KV-20M42/20S42/20S43/21MB42C/21MB42M/21MB42P/21ME42/21ME42C/
21SB42C/21SB42M/21SE42/21SE42C/21SE82/21SE82C
Display of Standby/Timer LED Flash Count
2 times
4 times
5 times
LED ON 0.3 sec.
LED OFF 0.3 sec.
LED OFF
3 sec.
Diagnostic Item
Flash Count*
+B overcurrent
2 times
Vertical deflection stopped
4 times
White balance failure
5 times
*One flash count is not used for self-diagnostic.
Stopping the Standby/Timer LED Flash
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY/TIMER LED from
flashing.
Self-Diagnostic Screen Display
For errors with symptoms such as "power sometimes shuts off" or "screen sometimes goes out" that cannot be confirmed, it is
possible to bring up past occurrences of failure on the screen for confirmation.
To Bring Up Screen Test
In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:
Display
Channel 5
Sound volume
Note that this differs from entering the service mode (sound volume
).
Power ON
+
Self Diagnostic Screen Display
SELF DIAGNOSTIC
2:
0
3:
N/A
0
4:
0
5:
1
101:
N/A
0
Numeral "0" means that no fault was detected.
Numeral "1" means a fault was detected one time only.
STANDBY/TIMER LED