KV-20S90 — Sony TV Service Manual (repair manual)

Model
KV-20S90
Pages
75
Size
8.53 MB
Type
PDF
Document
Service Manual
Brand
Device
TV
File
kv-20s90.pdf
Date

View Sony KV-20S90 Service Manual online

TRINITRON
®
 COLOR TELEVISION
  SERVICE MANUAL      
 
  
BA-4D
 
CHASSIS
        MODEL NAME 
REMOTE COMMANDER 
DESTINATION  
CHASSIS NO. 
Self Diagnosis
Supported model
KV-20S90
9-965-905-01
KV-20S90 
 
RM-Y155 
US 
SCC-S27NA
KV-21SE43C
 
RM-Y155 
SCC-S55BA
RM-Y155
Trinitron
— 2 —
KV-20S90 / 21SE43C
TABLE OF CONTENTS
 
Specifi cations.......................................................................................................................................3
 
Warnings and Cautions........................................................................................................................4
 
Safety Check-out .................................................................................................................................5
 
Self-Diagnostic Function......................................................................................................................6
1. Disassembly
 
1-1. Rear Cover Removal.....................................................................................................................8
 
1-2. Chassis Assembly Removal..........................................................................................................8
 
1-3. Service Position ............................................................................................................................8
 
1-4. Picture Tube Removal ...................................................................................................................9
 
 
Anode Cap Removal Procedure...................................................................................................9
2. Set-up Adjustments
 
2-1. Beam Landing...............................................................................................................................10
 
2-2. Convergence.................................................................................................................................11
 
2-3. Focus ............................................................................................................................................12
 
2-4. Screen (G2) ..................................................................................................................................12
 
2-5. Method of Setting the Service Adjustment Mode..........................................................................13
 
2-6. White Balance Adjustments ..........................................................................................................13
3. Safety Related Adjustments
 
3-1. X R582 Confi rmation Method (Hold Down Confi rmation) and Readjustments...........................14
 
3-2. B+ Voltage Confi rmation and Adjustment .....................................................................................14
4. Circuit Adjustments
 
4-1. Setting the Service Adjustment Mode...........................................................................................16
 
4-2. Memory Write Confi rmation Method .............................................................................................16
 
4-3. Remote Adjustment Buttons and Indicators .................................................................................16
 
 
Adjustment Items..........................................................................................................................17
 
4-4. A Board Adjustments ....................................................................................................................18
5. Diagrams
 
5-1. Circuit Boards Location.................................................................................................................21
 
5-2. Printed Wiring Board and Schematic Diagram Information ..........................................................21 
 
5-3. Block Diagram and Schematics ....................................................................................................22
 
 
Block Diagram ..............................................................................................................................22
 
 
A Board Schematic Diagram ........................................................................................................23
 
 
C Board Schematic Diagram........................................................................................................28
 
5-4. Semiconductors ............................................................................................................................30
6. Exploded Views
 
6-1. Chassis .........................................................................................................................................31
 
7. Electrical Parts List ......................................................................................................................................32
     SECTION TITLE 
PAGE
— 3 —
KV-20S90 / 21SE43C
Television system
American TV Standard/NTSC
Channel coverage
VHF: 2-13/ UHF: 14-69/ CATV: 1-125
Picture tube
Flat Trinitron
®
 tube
Visible screen size
20-inch picture measured diagonally
Actual screen size
21-inch measured diagonally
Antenna
75 ohm external terminal for VHF/UHF
Supplied Accessories
Remote Commander RM-Y155
Size AA (R6) batteries (2)
Telescopic Antenna (KV-21SE43C ONLY)
Optional Accessories
None
SPECIFICATIONS
Design and specifi cations are subject to change without notice.
1)   1 Vp-p 75 ohms unbalanced, sync negative 
2)   500 mVrms (100% modulation), Impedance:  47 kilohms
KV-21SE43C
KV-20S90
Power requirements
220V 50Hz
120V 60Hz
Number of Inputs/Outputs
Video 
1)
2
2
Audio Input 
2)
2
2
Speaker output (W)
4W x 2
3W x 2
Power Consumption (W)
In use (Max)
95W
90W
In Standby
1W
1W
Dimensions(W/H/D)
mm
522 x 477 x 479 mm
522 x 477 x 479 mm
in
20 
5
/
8
 x 18 
13
/
16
 x 18 
7
/
8
 in.
20 
5
/
8
 x 18 
13
/
16
 x 18 
7
/
8
 in.
Mass
kg
21.6 kg
21.6 kg
lbs
48 lbs
48 lbs
— 4 —
KV-20S90 / 21SE43C
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 identifi ed 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 identifi ed 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 la couche de carbone peinte sur le tube cathodique ou au blindage du tube cathodique.
Afi n d’eviter tout risque 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 du secteur.
ATTENTION AUX COMPOSANTS RELATIFS A LA SECURITE!!
Les composants identifi es par une trame et par une marque ! sur les schemas de principe, les vues explosees et les listes de 
pieces sont d’une importance 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 identifi es dans le present manuel. Suivre ces procedures lors de 
chaque remplacement de composants critiques, ou lorsqu’un mauvais fonctionnement suspecte.
— 5 —
KV-20S90 / 21SE43C
SAFETY CHECK-OUT
After correcting the original service problem, perform the following 
safety checks before releasing the set to the customer:
1.  Check the area of your repair for unsoldered or poorly soldered 
connections. Check the entire board surface for solder splashes and 
bridges.
2.  Check the interboard wiring to ensure that no wires are “pinched” or 
touching high-wattage resistors.
3.  Check that all control knobs, shields, covers, ground straps, and 
mounting hardware have been replaced. Be absolutely certain that 
you have replaced all the insulators.
4.  Look for unauthorized replacement parts, particularly transistors, 
that were installed during a previous repair. Point them out to the 
customer and recommend their replacement.
5.  Look for parts which, though functioning, show obvious signs of 
deterioration. Point them out to the customer and recommend their 
replacement.
6.  Check the line cords for cracks and abrasion. Recommend the 
replacement of any such line cord to the customer.
7.  Check the B+ and HV to see if they are specifi ed values. Make sure 
your instruments are accurate; be suspicious of your HV meter if sets 
always have low HV.
8.  Check the antenna terminals, metal trim, “metallized” knobs, screws, 
and all other exposed metal parts for AC leakage. Check leakage 
as described below.
Leakage Test
The AC leakage from any exposed metal part to earth ground and from 
all exposed metal parts to any exposed metal part having a return to 
chassis, must not exceed 0.5 mA (500 microamperes). Leakage current 
can be measured by any one of three methods.
1.  A commercial leakage tester, such as the Simpson 229 or 
RCA WT-540A. Follow the manufacturers’ instructions to use these 
instructions.
2.  A battery-operated AC milliampmeter. The Data Precision 245 digital 
multimeter is suitable for this job.
3.  Measuring the voltage drop across a resistor by means of a VOM 
or battery-operated AC voltmeter. The “limit” indication is 0.75 V, 
so analog meters must have an accurate low voltage scale. The 
Simpson’s 250 and Sanwa SH-63TRD are examples of passive VOMs 
that are suitable. Nearly all battery-operated digital multimeters that 
have a 2 VAC range are suitable (see Figure A).
How to Find a Good Earth Ground
A cold-water pipe is a guaranteed earth ground; the cover-plate retaining 
screw on most AC outlet boxes is also at earth ground. If the retaining 
screw is to be used as your earth ground, verify that it is at ground 
by measuring the resistance between it and a cold-water pipe with an 
ohmmeter. The reading should be zero ohms.
If a cold-water pipe is not accessible, connect a 60- to 100-watt trouble- 
light (not a neon lamp) between the hot side of the receptacle and the 
retaining screw. Try both slots, if necessary, to locate the hot side on the 
line; the lamp should light at normal brilliance if the screw is at ground 
potential (see Figure B).
To Exposed Metal 
Parts on Set
0.15  F
1.5 K 
AC
Voltmeter
(0.75 V)
Earth Ground
Trouble Light
AC Outlet Box
Ohmmeter
Cold-water Pipe
Figure A. Using an AC voltmeter to check AC leakage.
Figure B. Checking for earth ground.

Download Sony KV-20S90 Service Manual (Repair Manual)

Here you can view online or download Sony KV-20S90 Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair Sony KV-20S90 TV. Information contained in Sony KV-20S90 service manual (repair manual) typically includes:

  • Disassembly, troubleshooting, programming, maintenance, remote, adjustment, installation and setup instructions.
  • Schematics, wiring and block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Parts list (bill of materials).