Troubleshooting
GV 900…, GV 940…
k
3 - 12
GRUNDIG Service
englisch • English • anglais
Troubleshooting Diagram 11 – Head Servo
Head Servo Error
X703, C756, C757, IC701?
14.318MHz oscillation
at IC701-(37, 38)?
NO
in PB mode
YES
in REC mode
FG signal at IC701-(65)?
V-SYNC signal (reference)
at IC701-(50)?
YES
NO
Peripheral circuit of
IC701-(50), C746, C747
and R745?
NO
See Troubleshooting Diagram 10
– Head Switching Pulse
YES
YES
APC signal at IC701-(34)?
AFC signal at IC701-(32)?
NO
IC701?
YES
YES
Head motor control voltage
at IC702-(29)?
YES
Signal path between
IC701-(34, 32) and
IC702-(29)?
NO
NO
Low level at IC701-(58)?
IC702?
Signal path between IC702
and connector AD, flexprint
lead, headwheel motor?
Head switching pulse at
IC701-(23)?
Troubleshooting Diagram 12 – Capstan Servo
Capstan Servo does not work
PB mode
inoperative
YES
REC mode
inoperative
YES
YES
YES
NO
NO
NO
NO
Peripheral circuit of
IC701-(50), C746,
C747 and R745?
14.318MHz
oscillation
at IC701-(37, 38)?
Peripheral circuit of
X703?
NO
YES
NO
Control voltage at
IC701-(59)?
YES
NO
Power supplies
M12V/20V, PC5V?
Capstan motor?
IC701?
REC CTL signal
at output
IC701-(75, 74)?
PB CTL signal
at IC701-(76)?
A/C head?
Height adjustment
of A/C head?
Capstan AFC and
APC signal at
IC701-(31, 33)?
Capstan FG signal
at plug contact
AC-(6) /
IC701-(67)?
V-SYNC signal
(reference) at
IC701-(50)?
Are REC and/or PB
mode inoperative?
Troubleshooting Diagram 13 – Loop-through (E-to-E) Mode
No Picture Signal
in E-to-E Mode
NO
NO
NO
NO
YES
YES
YES
YES
Picture signal at input
IC201-(28, 30 or 31)?
Check signal paths:
– IC201-(28): from video input socket on the front?
– IC201-(30): from Euro-AV1 socket
(only for 1 Euro-AV socket)
– IC201-(31): from tuner or Euro-AV1 / 2 sockets
(only for 2 Euro-AV sockets)
5V at IC201-(12)?
PC5V power supply?
NO
Signal path between
IC201-(52) and IC701-(49)?
YES
YES
YES
Picture signal at
Q708-(E)?
Data and clock signal
at IC201-(63, 62)?
Signal paths between
IC701(56, 57) and
IC201-(63, 62)?
NO
5V at IC701-(51)?
IC701?
IC201?
NO
YES
Check PC 5V power
supply.
Picture signal at tuner
contact 6?
Picture signal at Q2801?
(only for 1 Euro-AV socket)
Picture signal at
IC2501-(19)?
(only for 2 Euro-AV sockets)
Picture signal at
IC2501-(20)?
Picture signal at output
IC201-(52)?
Picture signal at
IC701-(49)?
Picture signal at
IC701-(47)?
Picture signal at contact 19 of Euro-AV1 socket?
S. / P.
IC201
4-26
IC202
4-26
IC651
4-25
IC701
4-22
IC702
4-21
IC703
4-22
IC704
4-22
IC705
4-22
IC801
4-21
IC901
4-28
IC902
4-28
IC1601
4-33
IC1602
4-29
IC1701
4-36
IC1801
4-22
IC1901
4-35
IC1951
4-35
IC2501
4-24
IC5301
4-31
IC6301
4-24
RMC801 4-21
Tuner
4-30
