Sharp 20A1-RU User Manual

1
20A1-RU
21A1-RU
21A2-RU
1-21-1
SERVICE MANUAL
(20A1-RU, 21A1-RU) (21A2-RU)
COLOUR TELEVISION
Chassis No. UA-1
In the interests of user-safety (Required by safety regulations in some countries) the set should be restored
to its original condition and only parts identical to those specified should be used.
MODELS
SHARP CORPORATION
WARNING
The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug and power
receptacle, when servicing this chassis. To prevent electric shock, do not remove cover. No user – serviceable
parts inside. Refer servicing to qualified service personnel.
CONTENTS
» SPECIFICATIONS .............................. 2
» IMPORTANT SERVICE NOTES ......... 2
» ADJUSTMENT PRECAUTIONS ......... 3
» TROUBLE SHOOTING TABLE ......... 19
» HOTEL MODE APPLICATION .......... 21
» SOLID STATE DEVICE BASE
DIAGRAM ......................................... 22
» WAVEFORMS ................................... 23
» CHASSIS LAYOUT ........................... 24
» DESCRIPTION OF SCHEMATIC DIA-
GRAM ............................................... 26
» SCHEMATIC DIAGRAM
■ CRT Unit ....................................... 27
■ MAIN Unit ..................................... 28
» BLOCK DIAGRAM ............................ 34
» PRINTED WIRING BOARD ASSEM-
BLIES ................................................ 39
» REPLACEMENT PARTS LIST
■ ELECTRICAL PARTS ................... 44
■ MISCELLANEOUS PARTS........... 48
■ SUPPLIED ACCESSORIES ......... 48
■ PACKING PARTS ......................... 48
■ CABINET PARTS.......................... 49
Page Page
FEATURE
Ë
Multi 18 Systems
Ë
Full Auto Channel Preset and Auto Channel Skip
Ë
100-CH Program Memory
Ë
High Contrast Picture
Ë
Black Stretch Circuit
Ë
CATV (Hyper Band) Ready < Used Frequency Synthesizer
Tuner>
Ë
AVL (Sound Keeper) Function
Ë
Hotel Mode
Ë
On Timer / Sleep Timer / Reminder Timer
Ë
Colour Comb Filter Function (NTSC only)
Ë
Blue Back Noise Mute
Ë
Rear AV-In/Out Terminals and Front AV-In
Ë
English and Russian OSD
20A1-RU
21A1-RU
21A2-RU
SX0M220A1-RU/

Sharp 20A1-RU Specifications

General

Brand	Sharp
Model	20A1-RU
Category	TV
Language	English

Summary

WARNING

IMPORTANT SERVICE NOTES

SERVICE OF HIGH VOLTAGE SYSTEM AND PICTURE TUBE

Safety precautions for high voltage and CRT servicing.

X-RAY

Precautions regarding potential X-ray radiation during service.

BEFORE RETURNING THE RECEIVER

Final safety checks before returning the set to the user.

ADJUSTMENT PRECAUTIONS

PURITY ADJUSTMENT

PIF ADJUSTMENT

CONVERGENCE ADJUSTMENT

CRT CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT

HORIZONTAL AND VERTICAL DEFLECTION LOOP ADJUSTMENT

PAL CHROMA ADJUSTMENT

FUNCTION OPERATION CHECKING (VIDEO AND AUDIO)

TROUBLE SHOOTING TABLE

No Raster Troubleshooting

Steps to diagnose and fix the absence of a raster display.

No Picture or Sound Troubleshooting

Diagnosing issues with both picture and sound.

No Sound Troubleshooting

Steps to resolve no audio output.

Troubleshooting: Synchronization and Color Issues

Vertical and Horizontal Synchronization Problems

Diagnosing issues with vertical and horizontal sync.

Vertical Amplifier and Linearity Problems

Troubleshooting vertical amplifier and linearity faults.

No Vertical Scan Issues

Steps to diagnose and fix the absence of vertical scan.

Specific Color Issues

Troubleshooting problems related to color reproduction and white balance.

DESCRIPTION OF SCHEMATIC DIAGRAM

Critical Safety Precautions

Safety notes and warnings for servicing the unit.

SCHEMATIC DIAGRAM: CRT Unit

SCHEMATIC DIAGRAM: MAIN Unit

SCHEMATIC DIAGRAM - 1/3:MODEL 20/21A1-RU MAIN Unit

SCHEMATIC DIAGRAM - 2/3:MODEL 21A2-RU MAIN Unit

BLOCK DIAGRAM - 3/3:CRT Unit

PRINTED WIRING BOARD ASSEMBLIES

PARTS LIST