Sharp VC-H92HM Serviceanleitung Seite 58

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Check drum FG signal line.
FLOW CHART NO.16 DRUM SERVO TROUBLESHOOTING
Drum servo does not function.
1s there 10.0MHz oscillation at
pins (31) and (32) of 1€701?
YES
In PB mode
Check peripheral circuit of
X701.
In REC mode
Is the drum FG signal at pin (48) Is the reference signal (V-SYNC)
of iC701 present? at pin (64) of 1€701?
NO YES
Is the head switching pulse at NO partes by ma ie
pin (22) of IC701 present? (HEAD S
TROUBLESHOOTING.)
YES
Are the drum APC output at
pin (26) of IC701 andthedrum | NO
AFC output at pin (27) of 1C701
present?
Replace (C701.
YES
Is the drum control voltage
applied to pin (6) of AD
connector?
{s the drum control voltage
applied to pin (6) of ME
connector?
Does the drum error amplifier
circuit of 1C705 (pins (1), (2).and
(3)) operate normally?
YES
Is pin (38) of IC701 in high
impedance?
Replace drum motor.
NO
Check COMPOSIT-SYNC signal
line and FILTER (R714~715,
C718~721).
YES | Check harness between AD
and ME.
NO
NO
Replace 1C705.
Replace 1C701.