37VT-26H(GY)
54
YES
YES
YES
YES
YES
YES
YES
YES
NO
FLOWCHART NO. 1-11
DRUM SERVO TROUBLESHOOTING
Drum servo does not function.
Is there 16MHz
oscillation at pins (38)
and (39) of IC2001 ?
Is there the durm PG
signal at pin (90) of
IC2001 ?
Is there the reference
signal (V-sync.) at pin
(56) of IC2001 ?
Is there the head
switching pulse at pin
(18) of IC2001 ?
In REC mode
In PB mode
Is there the drum control
output at pin (77) of
IC2001 ?
Is there the durm FG
signal at pin (89) of
IC2001 ?
Check FG and PG signal
at pins (3) and (5) of the
connector ME and the
drum motor.
Check the signal line of
drum PG.
Is there the drum control
voltage applied to pin (7)
of connector AD ?
Check the composite
sync. signal at pin (14) of
IC2201, Q2217, Q2218
and Q7706 all the way up
to pin (56) of IC2001.
Check the signal line
between pin (7) of AD
and pin (77) of IC2001.
Check and replace the
drum motor.
See FLOWCHART NO.
1-8.
NO
NO
NO
NO
NO
NO
NO
Replace IC2001.
Check X7701, C7706
and C7707.
Replace IC2001.
Is pin (78) of IC2001 in
high impedance ?
