Sony DVP-FX921 Service Manual page 33

4. RF/Servo Circuit
Put disc in?
YES
Disc ID is correct?
YES
Does
spindle
rotate?
Check the cable connection between spindle and main PCBA
YES
Focus on OK?
YES
Track on OK?
YES
DISC is play?
DVP-FX921/FX921K/FX930/FX930CC/FX930WM/FX935
NO
Check the RF
NO
connection between HA1
U6 (MT1389LP)
Proper
NO
DMSO signal on
U6 (MT1389LP)?
YES
Proper signal
NO
on A, B, C, D of
U6 (MT1389LP)?
YES
Proper
RFO signal on
U6 (MT1389LP)?
YES
Check the cable connection on pick up head
Proper
NO
FOSO signal on
U6 (MT1389LP)?
YES
Proper
TRSO signal on
U6 (MT1389LP)?
YES
TR+&TR out
properly?
YES
Check cable connection on pick up head
NO
Check RF signal waveform
NO
NO
NO
NO
NO
NO
NO
8-5
No disc
Check the related
circuit on U6 (MT1389LP)
RF signal
Check DMSO related
circuit on U6 (MT1389LP)
Check connection
between U6 (MT1389LP)
and pick up head
Check the related
circuit on U6 (MT1389LP)
RFO signal
Check the related
circuit on U6 (MT1389LP)
Check the TRSO connection
on U6 (MT1389LP)
and motor driver
Check the tracking
control amp circuit
on motor driver