Servo Circuit - LG V9120W Service Manual

3. SERVO CIRCUIT

(1) Unstable Video in PB MODE
Unstable Video in
PB Mode.
YES
Does the Noise level of the
screen change
periodically?
YES
Does the CFG waveform
appear at the IC501
Pin67?
YES
On tracking do the CTL
pulses move?
YES
Does the Video Envelope
waveform appear at the
IC501 Pin82?
YES
Replace the IC501.
(2) When the Drum Motor
(2) doesn't run.
When the Drum Motor
doesn't run,
YES
Does 12V appear at the
PMC01 Pin8?
YES
Does 2.8V appear at the
PMC01 Pin12?
Check the connector
(PMC01) and the Drum
Motor Ass'y.
NO
Replace the IC501.
Refer to "When the Y signal
NO
doesn't appear on the
screen in PB Mode".
Refer to "(2)
No 12VA of Power section"
Do the Drum PWM Pulses
appear at the IC501
Pin34?
Aren't the foil patterns and
the Components between
IC501 Pin34 and PMC01
Pin12 short?
NO
Do the DFG Pulses appear
at the IC501 Pin104?
NO
Do the Drum PWM Pulses
appear at the IC501
Pin34?
Aren't the connecting patterns and the Components
between IC501 Pin34 and PMC01 Pin12 short?
3-8
NO
YES
YES
YES
NO
YES
NO
Do the DFG Pulses appear
at the PMC01 Pin11?
NO
Replace the Cap M.
Aren't the foil patterns and
the Components between
IC501 Pin 104 and PMC01
Pin11 short?
Replace the IC501.