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Sharp 20LK32 Service Manual

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20LK32
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.
» ELECTRICAL SPECIFICATIONS ......................................................................................................... 1
» IMPORTANT SERVICE SAFETY PRECAUTION ................................................................................. 2
» LOCATION OF USER'S CONTROL ..................................................................................................... 4
» INSTALLATION AND SERVICE INSTRUCTIONS ................................................................................ 5
» CHASSIS LAYOUT ............................................................................................................................. 13
» BLOCK DIAGRAM .............................................................................................................................. 15
» SCHEMATIC DIAGRAMS ................................................................................................................... 20
» PRINTED WIRING BOARD ASSEMBLIES ........................................................................................ 28
» REPLACEMENT PARTS LIST ............................................................................................................ 32
» PACKING OF THE SET ...................................................................................................................... 39
POWER INPUT ........................................ 110-220 V AC 50/60 Hz
POWER RATING
20LK32 ................................................................................ 72 W
20LK62 ................................................................................ 79 W
PICTURE SIZE .......................................... 1,194 cm
CONVERGENCE ............................................................. Magnetic
SWEEP DEFLECTION .................................................... Magnetic
FOCUS ............................................................... QPF Electrostatic
INTERMEDIATE FREQUENCIES
Picture IF Carrier Frequency ..................................... 45.75 MHz
Sound IF Carrier Frequency ...................................... 41.25 MHz
Color Sub-Carrier Frequency .................................... 42.17 MHz
AUDIO POWER
OUTPUT RATING
20LK32 ................................... 1.5 + 1.5 W (at 10% distortion)
20LK62 ................................... 3.0 + 3.0 W (at 10% distortion)

SERVICE MANUAL

20LK62
MODELS
CONTENTS
ELECTRICAL SPECIFICATIONS
SPEAKER
2
ANTENNA INPUT IMPEDANCE
TUNING RANGES
(Nominal)

SHARP CORPORATION

1
COLOR TELEVISION
Chassis No. MSA
20LK32
20LK62
SIZE ........................................................... 9 × 5 cm oval (2pcs.)
VOICE COIL IMPEDANCE
20LK32 ....................................................... 32 ohm at 400 Hz
VHF/UHF ..................................................... 75 ohm Unbalanced
VHF-Channels ............................................................... 2 thru 13
UHF-Channels ............................................................ 14 thru 69
CATV Channels ........................................................... 1 thru 125
Specifications are subject to change without
prior notice.
20LK32
20LK62
S81Z420LK32//
Page

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  Summary of Contents for Sharp 20LK32

  • Page 1: Table Of Contents

    CATV Channels ............1 thru 125 Color Sub-Carrier Frequency ........42.17 MHz (Nominal) AUDIO POWER Specifications are subject to change without OUTPUT RATING 20LK32 ........1.5 + 1.5 W (at 10% distortion) prior notice. 20LK62 ........3.0 + 3.0 W (at 10% distortion) SHARP CORPORATION...
  • Page 2: Important Service Safety Precaution

    20LK32 20LK62 IMPORTANT SERVICE SAFETY PRECAUTION Ë Service work should be performed only by qualified service technicians who are thoroughly familiar with all safety checks and the servicing guidelines which follow: WARNING X-RADIATION AND HIGH VOLTAGE LIMITS 1. For continued safety, no modification of any circuit 1.
  • Page 3: Safety Notice

    20LK32 20LK62 IMPORTANT SERVICE SAFETY PRECAUTION (Continued) • Connect the resistor connection to all exposed metal BEFORE RETURNING THE RECEIVER parts having a return to the chassis (antenna, metal (Fire & Shock Hazard) cabinet, screw heads, knobs and control shafts, escutcheon, etc.) and measure the AC voltage drop...
  • Page 4: Location Of User's Control

    20LK32 20LK62 LOCATION OF USER'S CONTROL Front Panel (20LK32) VIDEO/AUDIO TERMINALS (VIDEO/AUDIO terminals are also provided on the rear.) (20LK62) VIDEO/AUDIO TERMINALS POWER Press → On. Press again → Off. CHANNEL UP/DOWN (') Selects next higher channel. (") Selects next lower channel.
  • Page 5: Installation And Service Instructions

    20LK32 20LK62 INSTALLATION AND SERVICE INSTRUCTIONS Note: (1) When performing any adjustments to resistor controls and transformers use non-metallic screwdrivers or TV alignment tools. (2) Before performing adjustments, the TV set must be on at least 15 minutes. HIGH VOLTAGE CHECK CIRCUIT PROTECTION The receiver is protected by a 3.15A fuse (F701),...
  • Page 6 20LK32 20LK62 For adjustments of this model, the bus data is converted to various analog signals by the D/A converter circuit. Note: There are still a few analog adjustments in this series such as focus and master screen voltage. Follow the steps below whenever the service adjustment is required. See "Table-B" to determine, if serv- ice adjustments are required.
  • Page 7 20LK32 20LK62 SERVICE MODE (1) In the Service Mode, Key is used to select the mode in the following order. AGC & WHITE POINT GEOMETRIC ADJ. ADJ. MODE MODE MODE OFFSET ADJ. MODE FEATURE OPTION OPTION ADJ. MODE MODE MODE AGC &...
  • Page 8 20LK32 20LK62 OFFSET ADJ. ADJ. MODE MODE ↓ ↓ Y-D TIME (TV) [ YD ] (DL-TV) ATTENUATE INPUT SIGNAL LEVEL (ATT) ↓ ↓ Y-D TIME (AV) [ YD ] (DL-AV) VCO FREE RUNNING FREQUENCY ADJ. (VCO) ↓ ↓ INITIAL/DEFAULT LANGUAGE (INIT) STEREO, SAP, DBX FILTER ADJ.
  • Page 9: Service Mode

    20LK32 20LK62 SERVICE MODE DATA SERVICE REMARK ADJUST ITEM POSITION RANGE INITIAL VALUE FIX/ADJ AGC TAKE OVER POINT 0 ~ 63 V-LIN VERTICAL SLOPE 0 ~ 63 V-AMP VERTICAL AMP 0 ~ 63 V-CENT VERTICAL SHIFT 0 ~ 63 V-ZOOM...
  • Page 10 20LK32 20LK62 DATA SERVICE REMARK ADJUST ITEM POSITION RANGE INITIAL VALUE FIX/ADJ FMWS FM WINDOW SELECTION 0(disable) or 1(enable) SOUND MUTE BIT 0 (SM0) 0(disable) or 1(enable) SOUND MUTE BIT 1 0(disable) or 1(enable) AGC0 IF AGC SPEED BIT 0...
  • Page 11: Service Adjustment

    20LK32 20LK62 Ë SERVICE ADJUSTMENT RF AGC Adjustment 1. Receive a good local channel. 2. Enter the service mode signal category and select the service adjustment "AGC". 3. Set the data value to point where no noise or beat appears.
  • Page 12 20LK32 20LK62 CRT CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT No. Adjusting point Adjusting procedure/conditions Waveform and others CRT CUTOFF 1. Switch TV to VIDEO mode, BLUE BACK OFF, with ADJUSTMENT NO VIDEO signal. 3.5Vdc C BUS 2. Press R/C to set Picture Normal condition.
  • Page 13: Chassis Layout

    20LK32 20LK62 MODEL 20LK32 CHASSIS LAYOUT...
  • Page 14 20LK32 20LK62 MODEL 20LK62 CHASSIS LAYOUT...
  • Page 15: Block Diagram

    20LK32 20LK62 BLOCK DIAGRAM-1...
  • Page 16 20LK32 20LK62 MODEL 20LK32 BLOCK DIAGRAM-2...
  • Page 17 20LK32 20LK62 MODEL 20LK62 BLOCK DIAGRAM-2...
  • Page 18: Description Of Schematic Diagram

    20LK32 20LK62 DESCRIPTION OF SCHEMATIC DIAGRAM WAVEFORM MEASUREMENT CONDITIONS: NOTES: 1. Photographs taken on a standard gated color bar 1. The unit of resistance "ohm" is omitted. (K=k Ω =1000 Ω , M=M Ω ) signal, the tint setting adjusted for proper color. The wave shapes at the red, green and blue cathodes of 2.
  • Page 19 20LK32 20LK62 SCHEMATIC DIAGRAM: CRT Unit...
  • Page 20: Schematic Diagrams

    20LK32 20LK62 MODEL 20LK32 SCHEMATIC DIAGRAM: MAIN Unit...
  • Page 21 20LK32 20LK62 MODEL 20LK62 SCHEMATIC DIAGRAM: MAIN Unit...
  • Page 22 20LK32 20LK62 MODEL 20LK62 SCHEMATIC DIAGRAM: MTS MODULE Unit...
  • Page 23: Printed Wiring Board Assemblies

    20LK32 20LK62 PRINTED WIRING BOARD ASSEMBLIES PWB-A: MAIN Unit (Wiring Side)
  • Page 24 20LK32 20LK62 PWB-A: MAIN Unit (Chip Parts Side)
  • Page 25 20LK32 20LK62 PWB-B: CRT Unit (Wiring Side) PWB-B: CRT Unit (Chip Parts Side)
  • Page 26 20LK32 20LK62 PWB-E: MTS MODULE Unit (Wiring Side) (Only for 20LK62) PWB-E: MTS MODULE Unit (Chip Parts Side) (Only for 20LK62)
  • Page 27: Main Unit

    VHD1SS244//-1 J Diode å D603 RH-EX0667GEZZ J Zener Diode, 27V å D606 RH-DX0131CEZZ J Diode PWB-A DUNTKA541WEA2 – MAIN Unit (20LK32) — å D608 RH-DX0468CEZZ J Diode PWB-A DUNTKA541WEA3 – MAIN Unit (20LK62) — å PWB-B DUNTKA542WEA1 – CRT Unit —...
  • Page 28 20LK32 20LK62 Ref. No. Part No. Description Code Ref. No. Part No. Description Code PWB-A: DUNTK541WEA2 (20LK32) C333 VCEA0A1CW108M J 1000 16V EL. (20LK32) AD å PWB-A: DUNTK541WEA3 (20LK62) C333 RC-EZ1086CEZZ J 1000 16V EL. (20LK62) AD å C356 VCKYCY1HB472K J 4700p 50V...
  • Page 29 20LK32 20LK62 Ref. No. Part No. Description Code Ref. No. Part No. Description Code PWB-A: DUNTK541WEA2 (20LK32) R219 VRD-RA2BE392J J 3.9k 1/8W Carbon PWB-A: DUNTK541WEA3 (20LK62) R220 VRS-CY1JF221J J 220 1/16W M-Ox. R230 VRS-CY1JF473J J 47k 1/16W M-Ox. MAIN UNIT (Continued)
  • Page 30 VRS-CY1JF221J J 220 1/16W M-Ox. (20LK62) R804 VRS-CY1JF221J J 220 1/16W M-Ox. J409 QJAKF0074CEZZ X Jack, Rear AV-In (20LK32) AG R805 VRS-CY1JF822J J 8.2k 1/16W M-Ox. J409 QJAKG0093CEZZ X Jack, Rear AV-In (20LK62) AK R806 VRS-CY1JF123J J 12k 1/16W M-Ox.
  • Page 31: Crt Unit

    20LK32 20LK62 Ref. No. Part No. Description Code Ref. No. Part No. Description Code PWB-A: DUNTK541WEA2 (20LK32) PWB-B: DUNTK542WEA1 PWB-A: DUNTK541WEA3 (20LK62) CRT UNIT MAIN UNIT (Continued) TRANSISTORS P603 QPLGN0361CEZZ J Plug, 3-pin (TP651-3) P701 QPLGN0260CEZZ J Plug, 2-pin (M)
  • Page 32 20LK32 20LK62 Ref. No. Part No. Description Code Ref. No. Part No. Description Code PWB-E: DUNTK545WEA0 (20LK62) MTS MODULE UNIT INTEGRATED CIRCUITS IC3001 VHiCXA2074Q-1 J CXA2074Q IC3002 VHiMM1501XN-1 X MM1501XNRE TRANSISTORS Q3003 VS2SC3198-G-1 J C3198-G DIODE D3001 RH-EX0632GEZZ J Zener Diode, 9.9V CAPACITORS [EL.
  • Page 33: Packing Parts

    CCABA0139WEH0 X Front Cabinet Ass’y QCNW-2562PEZZ J Connecting Cord Not Available – Front Cabinet — TCAUH0102GJZZ X AV Notice Label (20LK32) GCOVA0110GJSA X Cover for LED, R/C TCAUS3000GJZZ X Caution Card HBDGB1001GJSA X Badge, "SHARP" TLABM0005GJZZ X Model Label JBTN-0114GJSA...
  • Page 34: Packing Of The Set

    20LK32 20LK62 PACKING OF THE SET Polyethylene Bag Operation Manual Infrared R/C Unit Batteries Wrapping Paper Buffer Material FRONT Packing Case Use tape to fix top side of pack case. REAR Use 12 staples fix the packing case. MARK : Not Replacement Items.
  • Page 35 20LK32 20LK62 COPYRIGHT © 2001 BY SHARP CORPORATION ALL RIGHTS RESERVED. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.

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