Sony DVP-FX720 Service Manual ▷ View online
9-3
Power is on
Does logo appear
on the screen?
Check power & clock
Does
the moving picture
of the DVD disc play
on the screen
normally?
Does
the moving picture
of the CD play
on the screen
normally?
Is MPEG data
signal normal?
Is error signal
normal?
Check CD/DVD
DSP output signal
Check MPEG decoder
input signal
Is clock normal?
Check clock signal
Check clock signal
Does the audio
signal output from MPEG
decoder?
Does the
audio sound output
normally?
2. MPEG Circuit
NO
NO
NO
YES
YES
YES
YES
YES
OK
OK
MT1389HD
MT1389HD
OK
OK
NO
YES
NO
NO
NO
YES
NO
NO
Check CD/DVD
DSP output signal
Check MPEG decoder
input signal
Check CD/DVD
DSP output signal
Check MPEG decoder
input signal
Is MPEG data
signal normal?
9-4
START
Power on
Power
green LED
on
Do all
the buttons work
normally?
Does
remote control work
normally?
Check P_3V3
Check IC MT1389
Does IR1 work
by testing waveform
normally?
Is battery OK?
Check
J9 on the
mainboard
Check IC MT1389
Replace IC MT1389
Replace IC MT1389
Replace battery
Replace IR1
Check the buttons
Is P_3V3 OK?
Do
the U2 work
normally?
Check power
Replace U2
3. Front Circuit (Dogotrpm & key)
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
YES
YES
NO
NO
NO
NO
YES
NO
NO
NO
9-5
Put disc in?
Disc ID is correct?
Does
spindle
rotate?
rotate?
Focus on OK?
Track on OK?
DISC is play?
Check RF signal waveform
Proper signal
on A, B, C, D of
MT1389
Proper
FO+ & FO signal
on MT1389
Proper
FOSO signal on
MT1389?
Check the related
circuit on MT1389
Check the TRSO
connection on MT1389
and motor driver
Check the tracking
control amp circuit
on motor driver
Proper
TRSO signal on
MT1389?
TR+ & TR out
properly?
Check cable connection on pick up head
Check the cable connection on pick up head
Check the related
circuit on MT1389
FO+ & FO signal
Check connection
between MT1389
and pick up head
Check the RF
connection between HA1
and MT1389
Proper
DMSO signal on
MT1389
Check the cable connection between spindle and main PCBA
Check the related
circuit on MT1389
RFL signal
Check DMSO related
circuit on MT1389
No disc (laser off)
4. RF/Servo Circuit
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
9-6E
Display condition
VCC5V normal
PNL_DVDD normal
VGH normal
VGL normal
Y1 operate
Video_Y, Video_C
Is M1, U3 OK?
Is U1 OK?
SDA, SCL signal
R, G, B signal output
TFT LCD normal
Check CN2
Check M2
Check BD2, BD3
Check BD4, BD5, BD6
Replace Y1
Check R19, R21, C25, R14, R17, R18, FB1, C24
Replace M1, U3
Replace U1
Check R24, R26, R31, R33
Check R8, R7, R5
Replace
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
VCCDC normal
Check CN2
YES
NO
NO
9-2. LCD TROUBLE SHOOTING GUIDE
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