Sharp QT-CD121 Service Manual
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Sharp QT-CD121 Service Manual

Sharp QT-CD121 Service Manual

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IMPORTANT SERVICE NOTES ........................................................................................................................................ 2
SPECIFICATIONS ............................................................................................................................................................. 2
NAMES OF PARTS ........................................................................................................................................................... 3
REMOTE CONTROL ......................................................................................................................................................... 3
DISASSEMBLY .................................................................................................................................................................. 4
REMOVING AND REINSTALLING THE MAIN PARTS ..................................................................................................... 5
ADJUSTMENT ................................................................................................................................................................... 6
BLOCK DIAGRAM ............................................................................................................................................................. 8
SCHEMATIC DIAGRAM / WIRING SIDE OF P.W.BOARD ............................................................................................. 10
NOTES ON SCHEMATIC DIAGRAM .............................................................................................................................. 16
TYPES OF TRANSISTOR ............................................................................................................................................... 16
WAVEFORMS OF CD CIRCUIT ...................................................................................................................................... 17
TROUBLESHOOTING ..................................................................................................................................................... 18
FUNCTION TABLE OF IC ................................................................................................................................................ 21
PARTS GUIDE/EXPLODED VIEW
SERVICE MANUAL
CONTENTS
SHARP CORPORATION
- 1 -
QT-CD121
• In the interests of user-safety the set should be restored to its
original condition and only parts identical to those specified should
be used.
This document has been published to be used
for after sales service only.
The contents are subject to change without notice.
QT-CD121
No. S5831QTCD121/
Page

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Summary of Contents for Sharp QT-CD121

  • Page 1: Table Of Contents

    QT-CD121 SERVICE MANUAL No. S5831QTCD121/ QT-CD121 • In the interests of user-safety the set should be restored to its original condition and only parts identical to those specified should be used. CONTENTS Page IMPORTANT SERVICE NOTES ............................2 SPECIFICATIONS ................................2 NAMES OF PARTS ................................

  • Page 2: Important Service Notes

    QT-CD121 FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS UNIT, PLEASE REFER TO THE OPERATION MANUAL. IMPORTANT SERVICE NOTES BEFORE RETURNING THE AUDIO PRODUCT (Fire & Shock Hazard) Before returning the audio product to the user, perform the following safety checks.

  • Page 3: Names Of Parts

    QT-CD121 NAMES OF PARTS 1. Cassette Compartment 2. CD Compartment 3. Tuning Control 4. (TAPE) Record Button: 5. (TAPE) Play Button: 6. (TAPE) Rewind Button: 7. (TAPE) Fast Forward Button: 8. (TAPE) Stop/Eject Button: 9. (TAPE) Pause Button: 4 5 6 7 8 9 10 11 10.

  • Page 4: Disassembly

    QT-CD121 DISASSEMBLY (C2)x1 (C1)x7 Caution on Disassembly ø3x10mm Switch PWB Follow the below-mentioned notes when disassembling the unit and reassembling it, to keep it safe and ensure excellent performance: 1. Take cassette tape and compact disc out of the unit.

  • Page 5: Removing And Reinstalling The Main Parts

    QT-CD121 REMOVING AND REINSTALLING THE MAIN PARTS CD MECHANISM SECTION Perform steps 1, 2, 3 and 5 of the disassembly method to remove the CD mechanism. (A1) x2 How to remove the pickup (See Fig. 5.) 1. Remove the screws (A1) x 2 pcs., to remove the shaft (A2) 2.6 x6mm...

  • Page 6: Adjustment

    QT-CD121 ADJUSTMENT MECHANISM SECTION TUNER SECTION • Driving Force Check fL: Low-range frequency fH: High-range frequency Torque Meter Specified Value • FM IF/RF PLAY: TW-2412 Over 120 g Specified Instrument Test Stage • Torque Check Value/Adjusting Connection Point Torque Meter...
  • Page 7 QT-CD121 CD SECTION Since this CD system incorporates the following automatic adjustment function, when the pickup is replaced, it is necessary to reajust it. Since this CD unit does not need adjustment, the combination of PWB and laser pickup unit is not restricted.

  • Page 8: Block Diagram

    QT-CD121 Figure 8 BLOCK DIAGRAM (1/2) – 8 –...
  • Page 9 QT-CD121 Figure 9 BLOCK DIAGRAM (2/2) – 9 –...

  • Page 10: Schematic Diagram / Wiring Side Of P.w.board

    QT-CD121 IC701 NO. VOLTAGE NO. VOLTAGE SWITCH PWB-A2 0.4V SW774 Q805 3.9V 3.1V TRACK DOWN/ S9012H 1.5V REVIEW 2.4V 4.1V 2.4V REMOTE SW773 4.1V 2.4V SENSOR R842 TRACK UP/ CUE 2.4V RX771 C849 2.4V 0.022 2.4V 0.4V 2.4V C848 SW771 0.4V...

  • Page 11: Pickup Unit

    QT-CD121 R801 TR– C801 0.01 FO– FO– R860 C847 FO– TR– 0.01 TR– R871 C850 4.7K PICKUP UNIT C845 4.7/50 R858 C841 0.047 XL801 EFLG XVSS DEFI 16.93MHz SBSY C842 VVss 0.047 ISET XOUT R838 C834 IC802 XVDD 0.033 R857...
  • Page 12 QT-CD121 330K ROD ANTENA 820K B.P.F. 0.022 (CH) LA1186N 0.022 1.2K 220/10 FM FRONT END FM BAND 0.022 0.0039 470P COVERAGE RF AMP. FM DET 1 2 3 6.8K 3.3/50 3.3/50 1N4148 MPX VCO CK 76kHz TRACKING NO. VOLTAGE LA1805 0.001...
  • Page 13 QT-CD121 HEADPHONES PWB-A4 MAIN PWB-A1(1/2) NO. VOLTAGE VOLTAGE R227 120 1.6V 1.2V (0V) 1.6V 1.9V (1.6V) R228 120 6V (6.3V) 1V (1.3V) AM SIGNAL 0.2V (0.7V) 1.7V 1.6V 1.5V (1.7V) FM SIGNAL 1.5V (1.5V) 0.4V (0.4V) 6.1V (6.4V) CD SIGNAL 2.5V...
  • Page 14 QT-CD121 HEADPHONES PWB-A4 1 2 3 1 2 3 4 CNP101 C351 CNP201 J201 FW202 HEADPHONES SW102 R228 R227 C353 B C E Q351 FW202 C354 D102 IC201 R203 C123 C203 R209 C207 C216 R205 R220 C201 C209 C234 R212...
  • Page 15 QT-CD121 SPEKERS SP502 SP501 R-CH L-CH COLOR TABLE BROWN RD(R) ORANGE CNS201 YELLOW SW601 M601 GREEN TAPE MAIN TAPE MOTOR BLUE (241-7) (241-6) VIOLET GRAY WH(W) WHITE TAPE BLACK ERASE HEAD RECORD/PLAYBACK (241-5) HEAD(241-4) PINK CNS101 (211) T601 TERMINAL PWB-A3...

  • Page 16: Notes On Schematic Diagram

    QT-CD121 NOTES ON SCHEMATIC DIAGRAM • Resistor: 1. Tuner To differentiate the units of resistors, the symbol as K and M ( ): AM mode are used: the symbol K means 1000 ohm and the symbol M Marking except for ( ): FM mode means 1000 kohm and the resistor without any symbol is an 2.

  • Page 17: Waveforms Of Cd Circuit

    QT-CD121 WAVEFORMS OF CD CIRCUIT STOP PLAY 50ms REVIEW 0.50 V 10.0 V IC801 20 F.E FOCUS SERCH 50ms 10.0 V 50ms 5.0 V 0.50 V IC801 54 DRF 50ms 1.00 V 0.5ms 10.0 V 0.5ms 0.5ms 1.00 V 10.0 V 0.5ms...

  • Page 18: Troubleshooting

    QT-CD121 TROUBLESHOOTING When the CD does not function When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check the following items.
  • Page 19 QT-CD121 • Playback can only be performed when a disc is loaded. Check the laser diode driver. Is the Focus servo active? (Can you hear it working?) Check the area around IC801(16) - (21) (focus servo circuit). Does the DRF signal change from "L" to "H"?
  • Page 20 QT-CD121 • Checking the spin system. Play operation is performed without disc. The spin driver circuit is normal. The turntable rotates a little. Check the periphery of IC801 pins 23 to 27, pin 39 and pin 40, The turntable fails to rotate or rotates at high speed.

  • Page 21: Function Table Of Ic

    QT-CD121 FUNCTION TABLE OF IC IC701 RH-iX0105AWZZ (IX0105AW): System Control Microcomputer Terminal Pin No. Port Name Input/ Function Name Output MTCONT2 Input/Output Used to input or output 4 bits at a time. When the output latch is set to "1", the unit will be in the input mode.
  • Page 22 QT-CD121 — M E M O — – 22 –...
  • Page 23 “HOW TO ORDER REPLACEMENT PARTS” To have your order filled promptly and correctly, please furnish the For U.S.A. only following information. Contact your nearest SHARP Parts Distributor to order. 1. MODEL NUMBER 2. REF. No. 3. PART NO. 4. DESCRIPTION For location of SHARP Parts Distributor, Please call Toll-Free;...
  • Page 24 QT-CD121 PRICE PRICE PART CODE DESCRIPTION PARTS CODE DESCRIPTION RANK RANK INTEGRATED CIRCUITS AB 0.022 µF,50V C14,15 VCKYPA1HF223Z AB 0.0047 µF,50V VCKYPA1HB472K AB 0.022 µF,50V VHILA1186N/-1 AE FM Front End,LA1186N VCKYPA1HF223Z AB 0.022 µF,50V VHILA1805//-1 AM FM/AF IF MPX.,LA1805 C20,21 VCKYPA1HF223Z AA 0.0039 µF,50V...
  • Page 25 QT-CD121 PRICE PRICE DESCRIPTION PARTS CODE DESCRIPTION PART CODE RANK RANK AB 0.033 µF,16V C834 VCTYPA1CU333M J R724 VRD-ST2EE153J AA 15 kohms,1/4W AB 0.1 µF,50V,Electrolytic C835 RC-GZA104AF1H R725 VRD-ST2CD153J AA 15 kohms,1/6W AB 10 µF,16V,Electrolytic C837 RC-GZA106AF1C R726 VRD-ST2CD102J AA 1 kohm,1/6W AE 0.01 µF,16V...
  • Page 26 QT-CD121 PRICE PRICE PART CODE DESCRIPTION PARTS CODE DESCRIPTION RANK RANK J201 QJAKM0007AWZZ J AF Jack,Headphones PCUSS0001SJZZ AB Cushion LCD701 RV-LX0001SJZZ AH LCD PRDAR0001SJZZ AD Heat Sink M601 9GD192112343W AX Motor with Pulley [Tape] LHLDA1001SJZZ AC Holder M701 RMOTV0408AFM3 J...
  • Page 27 QT-CD121 703x2 M701 M702 305x2 SW702 PWB-B Figure 4 CD MECHANISM EXPLODED VIEW – 27 – – 4 –...
  • Page 28 QT-CD121 601x3 PWB-A3 602x6 601x2 PWB-A5 230x2 603x2 PWB-A4 601x2 232-1 241 (241-1, 241-2 TAPE 241-3, 241-4, 241-5, MECHANISM 232-2 241-6, 241-7) SW761 603x4 MECHANISM 607x2 Silicon 605x3 Grease 603x4 604x3 SP501 SP503 PWB-A1 603x2 PWB-A2 603x5 LCD701 603x4 SP502 SP504 NOTE: The parts of cassette mechanism which are supplied are only the unit and consumable parts.

  • Page 29: Packing Of The Set

    QT-CD121 PACKING OF THE SET • Setting position of switches and knobs Tape Mechanism Control STOP STATE TUNING POWER/FUNCTION OFF/TAPE X-BASS SURROUND VOLUME Remote Control AC Power Supply Cord Polyethylene Bag, Unit SSAKH0001SJZZ Packing Case SPAKC0003SJZZ Feature Label Operation Manual Packing Add., Left/Right...
  • Page 30 QT-CD121 — M E M O — – 30 – – 7 –...
  • Page 31 QT-CD121 — M E M O — – 31 – – 8 –...
  • Page 32 QT-CD121 © COPYRIGHT 1998 BY SHARP COPORATION ALL RIGHTS RESERVED. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any from or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.

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