Read Sharp 37VT-26H Service Manual online
55
37VT-26H(GY)
YES
YES
FLOWCHART NO. 1-12
CAPSTAN SERVO TROUBLESHOOTING
Capstan servo does not function.
Is there 16MHz
oscillation at pins (38)
and (39) of IC2001 ?
Are REC and/or PB
mode inoperative ?
Does CTL amplifier
circuit of IC2001 (pins
(94) to (97)) operate
normally ? (Does the
noise appear at pin (97)
when touch R7759 by
hand ?)
Does PB CTL signal
appear at pin (97) of
IC2001 ?
YES
Check " A ".
Replace IC2001.
Check " B ".
In case of NO GOOD
Replace the capstan
motor.
Is the FFC AA-MH
normal ?
YES
Does the A/C head
operate normally ?
YES
Adjust the height of the
A/C head.
YES
YES
Does there appear the
capstan FG signal at pin
(87) of IC2001 ?
NO
YES
Check the capstan FG
signal line between AC
connector and IC2001.
Is there capstan control
signal at pin (76) of
IC7701 ?
YES
YES
Does there appear the
V-sync. at pin (56) at
IC2001 ?
Is there REC CTL signal
output at pins (95), (94)
of IC2001 ?
Is there the capstan
control voltage applied to
pin (4) of AC connector ?
Check X7701, C7706
and C7707.
NO
Only PB mode inoperative.
Only REC mode inoperative.
NO
NO
NO
Check pin (73) of IC2001.
NO
Check the composite
sync. signal line between
pin (14) of IC2201,
Q2217, Q2218 and
Q7706 all the way up to
pin (56) of IC2001.
Replace IC2001.
NO
YES
NO
Replace the FFC AA-MH.
NO
Replace A/C head.
NO
A
B
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