very good manual, with detail and clarity in esquematic diagrams and waveforms .
Text excerpt from page 40 (click to view)
NO.12 FLOW CHART NO.14
VC-GA57Z VC-GH97Z
The drum motor fails to run. No head switching pulse.
Is the voltage more than 2.6V NO DC given out pin(30) of IC701.
See FLOW CHART NO.12,13.
Check IC701. Is the drum motor rotating?
YES YES
Check PC 5V line. signal present on pins(66) and (65)
YES YES NO
Is the PG signal and drum FG Is the supply voltage of 5V feed to NO Are there drum PG M.M.signal at pin(3) IC706? pin(87) of IC701? of IC701, respectively? Check C753 and readjust R701. Check between pin(30) of IC701
YES
Is the voltage more than 2.6V NO and all the way up to pin(2) of (HEAD SW. POINT control.) applied at pin(2) of IC706? IC706.
YES Replace IC701.
Is the supply voltage of feed to Check AT 12V line. pin(21) of IC706? Are the PG and drum FG YES
Could be lines between IC706
NO
NO
YES and IC701.
signals present on pins(7) and (8) of IC706? Check peripheral circuit of IC706.
Check or replace drum motor.
FLOW CHART NO.13
40
Replace IC706.
NO
The drum motor runs only for a few seconds.
Is drum PG signal given out NO Check pin(4), (5), (6) of IC706 and pin(7) of IC706? periperal circuits.
YES
Check or replace drum motor.
Is drum PG signal given out of
pin(66) of IC701?
Check line between pin(7) of IC706 NO and all the way up thru to pin(66) of IC701.
YES
Is V-H.SW.P pulse given out of NO Check IC701. pin(23) of IC701?
