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Sharp VC-H992U Service Manual

Sharp VC-H992U Service Manual

Video cassette recorder
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1. GENERAL INFORMATION .............................. 4
1-1 FEATURES ................................................. 4
1-2 SPECIFICATIONS ..................................... 4
AND CONTROL ......................................... 5
MAIN PWB ASSEMBLY ............................. 7
PARTS .............................................................. 9
ADJUSTMENT JIG .................................. 11
5. ELECTRICAL ADJUSTMENT ........................ 30
POINT ....................................................... 31
SHARP CORPORATION
SERVICE MANUAL
MODELS
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 be used.
CONTENTS
Page
7. TROUBLESHOOTING ................................... 39
8. BLOCK DIAGRAM ..........................................50
10.PARTS LIST .................................................... 69
12.PACKING OF THE SET ................................. 81
This document has been published to be used for
after sales service only.
The contents are subject to change without notice.
1
VIDEO CASSETTE RECORDER
VC-H992U
VC-H992U ( A )
OF STILL PICTURE ................................. 31
5-3 CHECKING OF OFF TRACK ................... 31
SEPARATION ...........................................32
AND TROUBLESHOOTING GUIDE .............. 33
PATTERN ....................................................... 56
PARTS ............................................................ 77
VC-H992U/H992U(A)...Models for U.S.A.
VC-H992U
VC-H992U
VC-H992U(A)
VC-H992U(A)
SY8B1VC-H992U
Page

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Summary of Contents for Sharp VC-H992U

  • Page 1: Table Of Contents

    SERVICE MANUAL SY8B1VC-H992U VIDEO CASSETTE RECORDER VC-H992U VC-H992U ( A ) MODELS 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 be used.
  • Page 2 VC-H992U VC-H992U(A) IMPORTANT SERVICE NOTES BEFORE RETURNING THE VIDEO CASSETTE etc.) and measure the AC voltage drop across the RECORDER resistor. Reverse the AC plug on the set and repeat AC voltage measurements for each exposed part. Any reading of 0.45V rms (this corresponds to 0.3mA Before returning the video cassette recorder to the user, perform the following safety checks.
  • Page 3 VC-H992U VC-H992U(A) PRECAUTIONS IN PART REPLACEMENT When servicing the unit with power on, be careful to the section marked white all over. This is the primary power circuit which is live. When checking the soldering side in the tape travel mode, make sure first that the tape has been loaded and then turn over the PWB with due care to the primary power circuit.
  • Page 4: General Information

    VC-H992U VC-H992U(A) 1. GENERAL INFORMATION 1-1 FEATURES Common Features • EZ Set Up (automatically channel and clock set up) • CM Skip Search • 3-Language OSD • Instant Replay • 181-ch Cable Ready With Frequency Synthesizer • Automatic Playback Function Tuner •...
  • Page 5: Location Of Major Components And Control

    VC-H992U VC-H992U(A) 1-3 LOCATION OF MAJOR COMPONENTS AND CONTROL...
  • Page 6: Disassembly And Reassembly

    VC-H992U VC-H992U(A) 2. DISASSEMBLY AND REASSEMBLY TOP CABINET 2-1 DISASSEMBLY OF MAJOR BLOCKS : Remove 2 screws 1. TOP CABINET : Remove button 2. FRONT PANEL Remove 2 screws 3 and 7 clips 4. : Remove 1 screw 5. OPERATION SHIELD SHIELD ANGLE : Remove 2 screws 6 with shield angle.
  • Page 7: Disassembling The Mechanism/Main Pwb Assembly

    VC-H992U VC-H992U(A) 2-2 DISASSEMBLING THE MECHANISM/MAIN PWB ASSEMBLY 2. Removing the mechanism and cassette housing. 1. When removing the mechanism from the main PWB, Remove 2 screws 4 fixing the cassette housing to the remove the antenna cover 1 screw 1, and remove the mechanism, and remove the cassette housing.
  • Page 8: Cares When Reassembling

    VC-H992U VC-H992U(A) 2-3 CARES WHEN REASSEMBLING cassette housing. (Conditions: When mechanism and PWB INSTALLING THE CASSETTE HOUSING have been installed) When the cassette housing is installed on the mechanism, the initial setting is essential condition. 2. Mechanical initial setting There are two initial setting methods, namely electrical and Feed the pulley feed gear of loading motor with screw mechanical.
  • Page 9: Function Of Major Mechanical Parts

    VC-H992U VC-H992U(A) 3. FUNCTION OF MAJOR MECHANICAL PARTS (TOP VIEW) Function Function Full erase head Tu main brake Sup pole base ass’y Pinch drive cam Tension arm A/C head ass’y Idler ass’y Reverse guide Pinch drive lever ass’y Casecon drive gear...
  • Page 10 VC-H992U VC-H992U(A) FUNCTION OF MAJOR MECHANICAL PARTS (BOTTOM VIEW) Function Function Drum ass’y Reel belt Loading motor Clutch lever Drum drive motor Limiter pulley ass'y Tu pole base ass’y Shifter Slow brake Master cam Capstan D.D. motor...
  • Page 11: Adjustment, Replacement And Assembly Of Mechanical Units

    VC-H992U VC-H992U(A) 4. ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS The explanation given below relates to the on-site general service (field service) but it does not relates to the adjustment and replacement which need high-grade equipment, jigs and skill. For example, the drum assembling, replacement and adjustment service must be performed by the person who have finished the technical courses.
  • Page 12 VC-H992U VC-H992U(A) MAINTENANCE CHECK ITEMS AND EXECUTION TIME Perform the maintenance with the regular intervals as follows so as to maintain the quality of machine. Maintained 500 1000 1500 2000 Possible symptom Remarks Parts hrs. hrs. hrs. hrs. encountered Abnormal rotation or significant vi- Guide roller ass’y...
  • Page 13 VC-H992U VC-H992U(A) REMOVING AND INSTALLING THE CASSETTE Notes: HOUSING 1. When fitting the S/E sensor holder to the cassette controller frame L/R, take care. • Removal 2. Misengagement of teeth of casecon drive gear and drive 1. In the cassette removing mode, remove the cassette.
  • Page 14 VC-H992U VC-H992U(A) REEL DISK REPLACEMENT AND HEIGHT 4. Assemble the Sup main brake ass'y. CHECK Notes: • Removal 1. When installing the reel disk, take due care so that the 1. Remove the cassette housing control assembly. tension band ass'y is not deformed and grease does no 2.
  • Page 15 VC-H992U VC-H992U(A) Note: Notes: Whenever replacing the reel disk, perform the height check- 1. Hold the torque gauge by hand so that it is not moved. ing and adjustment. 2. Do not keep the reel disk in lock state. Do not allow long- time measurement.
  • Page 16 VC-H992U VC-H992U(A) Notes: CHECKING AND ADJUSTMENT OF TAKE-UP 1. Hold the torque gauge by hand so that it is not moved. TORQUE IN VIDEO SEARCH REWIND MODE 2. Do not keep the reel disk in lock state. Do not allow long- •...
  • Page 17 VC-H992U VC-H992U(A) CHECKING THE VIDEO SEARCH REWIND BACK TENSION • Remove the cassette housing control assembly. • After short-circuiting TP801 provided at the center Tension gauge Pinch roller (facing to the main PWB), plug in the power cord. 900 - 1,200g •...
  • Page 18 VC-H992U VC-H992U(A) 2. Visually check to see if the right edge of the tension pole Tension pole adjuster adjusting range is within the 2.3 ± 0.25 from the right edge of the Sup guide shaft. Tension pole adjuster Sup guide shaft Tension pole 2.3 ±...
  • Page 19 VC-H992U VC-H992U(A) • Adjustment • Checking the brake torque at the take-up side 1. If the indication of torque cassette meter is lower than the setting, shift the tension spring engagement to the part A. Torque gauge 2. If the indication of torque cassette meter is higher than the setting, shift the tension spring engagement to the part B.
  • Page 20 VC-H992U VC-H992U(A) REPLACEMENT OF A/C (Audio/Control) HEAD 3. Align the left end of gear of A/C head arm with the punched mark of chassis, tentatively tighten the screws 1. Remove the cassette housing control assembly. 1 and 2 so as to ensure smooth motion of A/C head 2.
  • Page 21 VC-H992U VC-H992U(A) A/C HEAD HEIGHT ROUGH ADJUSTMENT HEIGHT ADJUSTMENT OF REVERSE GUIDE • Setting 1. Adjust the height from the mechanism chassis to the Azimuth screw reverse guide lower flange to 13.38 mm, using the reverse guide height adjustment jig, in tape loading state.
  • Page 22 VC-H992U VC-H992U(A) ADJUSTMENT OF TAPE DRIVE TRAIN Notes: 1. Previously set the tracking control in the center position, 1. Tape run rough adjustment and adjust the envelop waveform to maximum with X 1 Remove the cassette housing control assembly. value adjustment nut. Thereby the tape run rough ad- 2 After shortcircuiting TP801 provided at the center justment is facilitated.
  • Page 23 VC-H992U VC-H992U(A) 3 Next, change the alignment tape to VROEFZCS or VROEFZHS to playback. Press the tracking button PB CHROMA (+), (–) and change the envelope waveform from Envelope max to min and from min to max. At this time adjust...
  • Page 24 VC-H992U VC-H992U(A) REPLACEMENT OF DRUM D.D. MOTOR REPLACEMENT OF THE CAPSTAN D.D. 1. Set the ejection mode. (DIRECT DRIVE) MOTOR 2. Withdraw the main power plug from the socket. • Remove the mechanism from the main PWB (refer to Page 7 "1. When removing the mechanism from the •...
  • Page 25 VC-H992U VC-H992U(A) REPLACING THE UPPER AND LOWER DRUM ASSEMBLING OF PHASE MATCHING ASSEMBLY MECHANISM COMPONENTS • Assemble the phase matching mechanism compo- • Replacement (Perform in the numerical order) nents in the following order. 1 Remove the motor as stated in Page 24 D.D. motor 1.
  • Page 26 VC-H992U VC-H992U(A) 1Insert Reverse Guide Lever Ass’y Insert reverse guide lever ass'y 2 Insert pinch drive cam Align here. Turn the reverse guide lever assembly counterclockwise Fit the pinch drive cam so that the notch of pinch to the stopper.
  • Page 27 VC-H992U VC-H992U(A) 1. Make sure that the loading gear is at the point 1 as INSTALLING THE SHIFTER shown below. 2. Install, paying attention to insert point 5 and release point 3. Drum 3. For the phase matching at the insert point 1, see the point 2 as shown below.
  • Page 28 VC-H992U VC-H992U(A) INSTALLING THE MASTER CAM (AT REAR REPLACEMENT OF LOADING MOTOR • Removal SIDE OF MECHANISM CHASSIS) 1. Make sure beforehand that the shifter is at the point as shown below. 2. Place the master cam in the position as shown below.
  • Page 29 VC-H992U VC-H992U(A) ASSEMBLY OF CASSETTE HOUSING 1. Drive Gear and R Drive angle ass’y MSPRT0381AJFJ Apply grease Apply grease Apply grease Figure 4-47. 2. Synchro Gear, Drive Gear L and Drive Gear R LANGF9592AJFW Top surface should be free from scratches or soil.
  • Page 30: Electrical Adjustment

    VC-H992U VC-H992U(A) 5. ELECTRICAL ADJUSTMENT Notes: • Before the adjustment: Electrical adjustments discussed here are often required after replacement of electronic components and mechanical parts such as video heads. Check that the mechanism and all electric components are in good working condition prior to the adjustments,otherwise adjustments can not be completed.
  • Page 31: Adjustment Of Head Switching Point

    VC-H992U VC-H992U(A) SERVO CIRCUIT ADJUSTMENT 5-2 ADJUSTMENT OF FV (False Vertical Sync) OF STILL PICTURE 5-1 ADJUSTMENT OF HEAD SWITCHING Measuring Color TV monitor POINT instrument Measuring Dual-trace oscilloscope Mode Playback still instrument Cassette Self-recorded tape (SP mode) Mode Playback...
  • Page 32: Adjustment Of Sif-Input Level

    VC-H992U VC-H992U(A) MTS CIRCUIT ADJUSTMENT (HI-FI MODELS ONLY) 5-4 ADJUSTMENT OF SIF-INPUT LEVEL Measuring AC milli-voltmeter and RF signal instrument generator. Mode Input signal RF CH-10 (at 300Hz 30% MOD.) Test point AUDIO OUT jack (R channel) Control R142(S-IF ADJ.)
  • Page 33: Mechanism Operation Flowchart And Troubleshooting Guide

    VC-H992U VC-H992U(A)
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  • Page 39: Troubleshooting

    VC-H992U VC-H992U(A)
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  • Page 50: Block Diagram

    VC-H992U VC-H992U(A) 8. BLOCK DIAGRAM SYSTEM SERVO BLOCK DIAGRAM...
  • Page 51 VC-H992U VC-H992U(A)
  • Page 52 VC-H992U VC-H992U(A) SIGNAL FLOW BLOCK DIAGRAM...
  • Page 53 VC-H992U VC-H992U(A) Playback luminance signal Playback chroma signal Audio playback signal E-E signal Recording luminance signal Recording chroma signal Audio recording signal E-E signal(Audio)
  • Page 54 VC-H992U VC-H992U(A) POWER CIRCUIT BLOCK DIAGRAM...
  • Page 55 VC-H992U VC-H992U(A) SCHEMATIC DIAGRAM • The indicated voltages in the following diagram IMPORTANT SAFETY NOTICE: are measured with an SSVM, upon receiving color bars (400 Hz sound signal) in either the PARTS MARKED WITH " å " ( ) ARE...
  • Page 56: Schematic Diagram And Pwb Foil Pattern

    VC-H992U VC-H992U(A) 9. SCHEMATIC DIAGRAM AND PWB FOIL PATTERN MAIN CIRCUIT(1) * VOLTAGE MEASUREMENT MODE PB ..Parentheses ( REC ..Without Parentheses...
  • Page 57 VC-H992U VC-H992U(A)
  • Page 58 VC-H992U VC-H992U(A) MAIN CIRCUIT(2) * VOLTAGE MEASUREMENT MODE PB ..Parentheses ( REC ..Without Parentheses...
  • Page 59 VC-H992U VC-H992U(A)
  • Page 60 VC-H992U VC-H992U(A) MAIN CIRCUIT(3) * VOLTAGE MEASUREMENT MODE PB ..Parentheses ( REC ..Without Parentheses...
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  • Page 62 VC-H992U VC-H992U(A) MAIN CIRCUIT(4) * VOLTAGE MEASUREMENT MODE PB ..Parentheses ( REC ..Without Parentheses...
  • Page 63 VC-H992U VC-H992U(A)
  • Page 64 VC-H992U VC-H992U(A) OPERATION CIRCUIT * VOLTAGE MEASUREMENT MODE PB ..Parentheses ( REC ..Without Parentheses...
  • Page 65 VC-H992U VC-H992U(A) PWB FOIL PATTERN OPERATION PWB...
  • Page 66 VC-H992U VC-H992U(A) MAIN PWB...
  • Page 67 VC-H992U VC-H992U(A)
  • Page 68 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code - M E M O -...
  • Page 69: Parts List

    V 2SC2412KQ 3. PART NO. 4. DESCRIPTION Q651 VS2SD1306-E1E V 2SD1306 Q652 VS2SD1306-E1E V 2SD1306 In USA: Contact your nearest SHARP Parts Distributor to order. Q653 VSUN2113///-1 V UN2113 For location of SHARP Parts Distributor, Q654 VSUN2212///-1 V UN2212 Q656 VSUN2212///-1 V UN2212 Please CallToll-free;...
  • Page 70 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code å D923 VHD15DF1FC/1E V 15DF1FC C218 VCKYCY0JF105Z 6.3V Ceramic å D924 VHD10ELS4//-1 V 10ELS4 C219 VCKYCY1CF104Z V 0.1 16V Ceramic å D926 VHD10ELS4//-1 V 10ELS4 C220 VCKYCY1CF104Z V 0.1...
  • Page 71 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code C657 VCKYCY1EB153K V 0.015 25V Ceramic C786 VCKYCY1CF334Z V 0.33 16V Ceramic C658 VRS-CY1JF000J 1/16W Metal Oxide C787 VCFYHA1HA474J V 0.47 C659 VRS-CY1JF000J 1/16W Metal Oxide C789 VCKYCY1EB103K V 0.01...
  • Page 72 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code R207 VRS-CY1JF101J V 100 1/16W Metal Oxide R686 VRS-CY1JF102J V 1k 1/16W Metal Oxide R225 VRS-CY1JF750J V 75 1/16W Metal Oxide R690 VRS-CY1JF000J 1/16W Metal Oxide...
  • Page 73 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code R801 VRS-CY1JF000J 1/16W Metal Oxide S809 QSW-K0002AJZZ V Switch, Set R802 VRS-CY1JF000J 1/16W Metal Oxide S810 QSW-K0002AJZZ V Switch, CH+ R803 VRS-CY1JF000J 1/16W Metal Oxide S811...
  • Page 74 MLEVF0519GEZZ J Supply Loading Arm Ass’y AF (VC-H992U(A)) (VC-H992U(A)) NGERH1295AJ00 V Master Cam(VC-H992U) MLEVF0499AJZZ V Pinch Drive Lever Ass’y NGERH1295GE00 J Master Cam(VC-H992U(A)) AE (VC-H992U) NGERH1294AJZZ V Casecon Drive Gear MLEVF0499GEZZ J Pinch Drive Lever Ass’y (VC-H992U) (VC-H992U(A)) NGERH1294GEZZ J Casecon Drive Gear MLEVF0500GEZZ J Pinch Roller Lever Ass’y...
  • Page 75 Ref. No. Part No. Description Code Ref. No. Part No. Description Code PREFL1011AJZZ V Light Guide(VC-H992U) LANGF9592GEFW J Upper Plate(VC-H992U(A)) AL PREFL1011GEZZ J Light Guide(VC-H992U(A)) AE LHLDX1028AJ00 V Frame (L)(VC-H992U) QCNW-8022AJZZ V FFC for Drum Motor LHLDX1028GE00 J Frame (L)(VC-H992U(A)) LHLDX1030AJZZ...
  • Page 76 LHLDZ1962AJ00 V Sensor LED Cover SPAKC3998EJZZ - Packing Case — PGUMS0026AJZZ V Foot Rubber (VC-H992U(A)) TLABM3920AJZZ V Model Label(VC-H992U) SPAKX1044AJZZ - Packing Add. (VC-H992U) — TLABM3961EJZZ K Model Label SPAKX1047EJZZ - Packing Add. — (VC-H992U(A)) (VC-H992U(A)) XJPSD30P10WS0 V Screw SPAKP0114AJZZ - Form Bag (VC-H992U) —...
  • Page 77: Exploded View Of Mechanical Parts

    VC-H992U VC-H992U(A) 11. EXPLODED VIEW OF MECHANICAL PARTS Ref. No. Part No. Description Code Ref. No. Part No. Description Code MECHANISM CHASSIS PARTS...
  • Page 78 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code CASSETTE HOUSING CONTROL PARTS...
  • Page 79 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code CABINET PARTS...
  • Page 80 VC-H992U VC-H992U(A) Ref. No. Part No. Description Code Ref. No. Part No. Description Code FRONT PANEL PARTS 500-7 500-3 500-2 500-1 500-5 500-4 PRECAUTION ON FRONT PANEL SET-UP Cassette cover Front panel Cassette housing Cassette cover open lever Cassette cover...
  • Page 81: Packing Of The Set

    Operation Manual (VC-H992U) TiNS-3499EJZZ Operation Manual (VC-H992U(A)) TGAN-0001AJZZ Guarantee Card (VC-H992U) TGAN-0001EJZZ Guarantee Card (VC-H992U(A)) TCADH3051AJZZ Timer Card(VC-H992U) TCADH3051EJZZ Timer Card(VC-H992U(A)) Dry Battery RRMCG0235AJSB Infrared Remote Control Unit SSAKA0001AJZZ(VC-H992U) SSAKA0001EJZZ(VC-H992U(A)) Polyethylene Bag SPAKP0114AJZZ (VC-H992U) QCNW-0322AJZZ SPAKP0098EJZZ (VC-H992U(A)) 75 ohm Coaxial Cable...
  • Page 82 Code Ref. No. Part No. Description Code COPYRIGHT C 1999 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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