43
VC-A422U
VC-H822U
FLOW CHART NO.15
Drum servo does not function.
Check peripheral circuit of X701.
Is there a 14.318MHz oscillation at
pins(37) and (38) of IC701?
NO
In PB mode
YES
In REC mode
Is there drum FG signal at pin(65)
of IC701 present?
Is the V-SYNC signal(reference) at
pin(50) of IC701?
YES
NO
NO
Check peripheral circuit of pin(50) of
IC701, C715, C716 and R708.
Check drum FG signal line.
Is the head switching pulse at pin(23)
of IC701 present?
NO
See
FLOW CHART NO.15
.
YES
YES
Is the drum APC output at pin(34) of
IC701 and drum AFC output at
pin(32) of IC701 present?
NO
Replace IC701.
YES
YES
Is the drum control voltage applied
to pin(2) of IC706?
YES
Is pin(30) of IC701 in high
impedance?
NO
YES
NO
Check the line between pins(34) and
(32) of IC701 and pin(2) of IC706.
Does the IC706 operate normally?
Replace IC701.
Replace drum motor.
Summary of Contents for VC-A422U
Page 51: ...VC A422U VC H822U VC A422U VC H822U 52 53 SIGNAL FLOW BLOCK DIAGRAM VC A422U ...
Page 52: ...VC A422U VC H822U VC A422U VC H822U 54 55 SIGNAL FLOW BLOCK DIAGRAM VC H822U ...
Page 53: ...56 VC A422U VC H822U POWER CIRCUIT BLOCK DIAGRAM ...
Page 63: ...72 VC A422U VC H822U M E M O ...
Page 76: ...85 VC A422U VC H822U M E M O ...
