Sharp VC-MH80 User Manual

VC-M H80
VC-M H90
SHA@l= SERVICE MANUAL
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S04FZVC-MH80l
lvusi VIDEO CASSEITE RECORDER
VC-MH80
MODELS VC-MH90
In the interests of user-safety (Required by safety regu-
lations in some countries) the set should be restored
CONTENTS
Page
1 . SPECIFICATIONS .._........_.........................................._..............._...........................
3
2. DISASSEMBLY AND REASSEMBLY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3. FUNCTION OF MAJOR MECHANICAL PARTS . . . . . . . .._..........................................
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4, ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS . . . .
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5. ELECTRICAL ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . .._................................_.........._........
34
6. MECHANISM OPERATION FLOW CHART AND TROUBLESHOOTING GUIDE . 43
7. TROUBLESHOOTING
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49;
8. BLOCK DIAGRAMS . . . . . . . . . . . . .._......._..._..................._.._......_...._........................._.._....
67
9. CIRCUIT DIARAM AND
PWB
FOIL PATTERN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
75
10. REPLACEMENT PARTS LIST
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
105
1 1 . EXPLODED VIEWS . . . . . . ..r........................................................._............................ 127
12. PACKING OF THE SET . . . . . . . . . . . . . . . . . . . . . .._................................................................. 131
SHARP CORPORATION

Sharp VC-MH80 Specifications

General

Brand	Sharp
Model	VC-MH80
Category	VCR
Language	English

Summary

Precautions in Part Replacement

1. Specifications

2. Disassembly and Reassembly

Disassembly of Major Blocks

Steps for disassembling main blocks like top cabinet, front panel, and PWB units.

Reassembly Precautions

Guidelines for reassembling the cassette controller and coupling the mechanism to the PWB.

3. Mechanical Parts Functionality

Mechanical Parts Views (Top and Bottom)

Description of functions for key mechanical parts viewed from top and bottom.

4. Mechanical Unit Adjustments and Maintenance

Tools for Mechanical Adjustments

List of specialized tools required for mechanical adjustments and maintenance.

Reel Disk Replacement and Adjustment

Procedures for replacing, checking height, and adjusting reel disks.

Brake Torque Checking and Adjustment

Steps for checking and adjusting brake torque on supply and take-up sides.

Head Replacement and Adjustment

Procedures for replacing and adjusting the AK (Audio/Control) head.

Tape Drive Train and Guide Adjustments

Adjusting tape path, rollers, head, and X-position for optimal tape drive.

Motor Replacement Procedures

Procedures for replacing capstan, drum, and loading motors.

Mechanism Assembly and Phase Matching

Steps for assembling mechanism parts and ensuring phase matching.

Mechanical Parts Requiring Periodical Inspection

5. Electrical Adjustments

Required Instruments and Precautions

List of instruments and important notes before performing electrical adjustments.

Servo Circuit Adjustments

Adjustments for PAL and NTSC systems, including head switching and tracking.

Y/C and Hi-Fi Audio Circuit Adjustments

Adjustments for video signal levels, Hi-Fi audio, and related circuits.

6. Mechanism Operation and Troubleshooting

Mechanism Operation Flow Charts

Diagrams detailing mechanism operation for various modes.

Mechanism Troubleshooting Guide

Flow charts for diagnosing mechanism failures and unusual sounds.

7. Troubleshooting Flowcharts

Power, Timer, and Remote Control Troubleshooting

Flow charts for diagnosing power, timer, and remote control issues.

Cassette, Motor, and System Control Troubleshooting

Flow charts for cassette loading, motor, and system control problems.

Circuit Troubleshooting

Flow charts for diagnosing issues in video, audio, Y/C, and Hi-Fi circuits.

Shuttle Function Description

Shuttle Ring Operation and Logic

Explains shuttle ring functions, logic, specifications, and mode sequences.

IC703 (E2PROM) Replacement and Reprogramming

E2PROM Replacement and Reprogramming

Procedures for replacing and reprogramming the E2PROM memory function.

8. Block Diagrams

System Block Diagrams

Diagrams showing servo process, signal flow, audio, and power circuits.

Schematic Diagram and Notes

Schematic Diagram and Measurement Notes

Schematic diagram with safety notes, cautions, and measurement condition guidelines.

9. Circuit Diagrams and PWB Foil Patterns

Circuit Diagrams

Detailed circuit diagrams for main, head amp, timer, OSD, chroma, MPX, and IF sections.

PWB Foil Patterns

Foil patterns for main and sub-assembly printed wiring boards.

10. Replacement Parts List

Parts List Introduction and Component Identification

Information on safety, ordering, and identifying components.

Component Lists by Category

Detailed lists of diodes, coils, transformers, controls, capacitors, resistors, ICs, and transistors.

Mechanical, Housing, and Miscellaneous Parts

Lists of mechanical, cassette housing, front panel, and miscellaneous parts.

IF Unit and Supplied Accessories

Lists of IF unit components and supplied accessories.

11. Exploded Views

Exploded Views of Major Assemblies

Diagrams showing exploded views of mechanism chassis, cassette housing, mechanical, and front panel parts.

12. Packing of the Set

Knob Setting Positions for Packing

Specifies knob positions for RF converter and test signal switch during packing.

Supplied Accessories for Packing

Lists accessories included with the set for packing.