Sharp 13VT-N100 - Capstan Servo Troubleshooting

46
13VT-N100
13VT-N150
13VT-CN10
NO
NO
NO
NO
NO
NO NO
NO
CAPSTAN SERVO TROUBLESHOOTING FLOW CHART NO.1-11
YES YES
YES
YES
NO
NO
YES YES YES
YES
YES
YES YES YES
NO
Is pin (78) of IC2001 normal?
Replace the capstan motor.
Replace IC2001. Replace IC2001.
Replace the FFC AA-MH.
Check X7701, C7707 and C7706.
Check the capstan FG signal line between AC connector and IC2001.
Does there appear the capstan FG signal at pin (87) of IC2001? Is there the capstan control voltage applied to pin (4) of AC connector?
Check the composite sync. signal at pin (41) of IC401, Q404 and Q428 up to pin (56) of IC2001.
Replace IC2001.
Replace A/C head.
Check " A " Check " B "
In case of NO GOOD
Does there appear the V- sync. at pin (56) at IC2001?
Is there REC CTL signal output at pins (94), (95) of IC2001?
Is there capstan control signal at pin (76) of IC2001?
Are REC and /or PB mode inoperative?
Is the FFC AA-MH normal? Does the A/C head operate normally?
Adjust the height of the A/C head.
Does PB CTL signal appear at pin (97) of IC2001?
Does CTL amplifier circuit of IC2001 (pins (95) to (97)) operate normally? (Does the noise appear at pin (97) when touch R7759 by hand?)
Only PB mode inoperative. Only REC mode inoperative.
A
B
Is there 16MHz oscillation at pins (38) and (39) of IC2001.
Capstan servo does not function.