Jvc TT 81 Service Manual

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TT-81

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Specifications ........................................................ 2
Features ............................................................ 3
New Technical Information
3-(1) Block Diagram ................................................. 4
3-(2) Crystal Oscillator and Frequency Deviders ............................... 5
3-(3) Neon Lamp Circuit .............................................. 5
3-(4) Frequency Generator, Output Amp. Waveform and Phase Comparison ............ 6
3455) Drive Circuit .................................................. 7
3-(6) Reverse Turn Detection ........................................... 7
3-(7) Start/Stop Circuit ............................................... 8
348) Cut-off of Hall Element Drive Circuit .................................. 8
3491 Quick Stop Circuit .............................................. 8
Dismounting ......................................................... 9
Adjustment Procedures
5-") Power Supply Voltage ............................................ 10
5-(2) Lock Adjustment ............................................... 10
5-(3) Quick Stop Adjustment ........................................... 1 1
5-(4) Wow and Flutter Adjustment ....................................... 11
5-(5) Speed Adjustment .............................................. 1 1
Connections Wiring ..................................................... 12
Lubrication .......................................................... 12
Waveforms .......................................................... 13
Troubleshootings
9-(1) Turntable does not rotate .......................................... 14
9-(2) Turntable rotates at high speed and fails to stop ........................... 15
9-(3) Speeds increase when rotated in the reverse direction ....................... 16
9-(4) Neon Lamp does not light ......................................... 16
9-(5l Neon Lamp remains lit ........................................... 16
9-(6) Turntable rotates at an incorrect rpm .................................. 17
9-0) Speed Select button does not function ................................. 18
9-(8l Quick Stop does not function ....................................... 18
Exploded View and Parts List .............................................. 19
TAS-1QC Servo Control and Power Supply P.C. Board Ass'y ......................... 21
Packing Material Parts List ................................................ 26
Accessories List ....................................................... 27
Parts List with Specified Number for Designated Areas ............................. 27
Schematic Diagram ..................................................... 28
Diagram of TAS-1SC Printed Circuit Board Ass'y ................................. 29

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