Sharp DV-550U Service Manual page 27

NO DVD VIDEO3 AND AUDIO BUT CD AUDIO OK
Does opening screen come up.
Yes
Check pin 148 of IC601 for data
cannot be constant high.
Yes
Check for MPEG DATA at IC601
pins 149, 151-154,156-158.
No
Check pin 48 of IC402 for
RF signal.
No
Replace IC303.
GOOD DVD AUDIO AND NO CD AUDIO
Check pin 5 of IC601 for data.
Yes
Check pin 114 of IC601 for data.
Yes
Check IC801 and IC6001
No
Check IC501.
Is Vcc on pin 37.
Yes
Is chip enable pin 26 low.
Yes
Change IC501.
No
Chenge IC601.
Yes
Yes
Check multiple Vcc
supply pins.
Yes
Check pin 95 reset must
be low.
Yes
Check pins 53-56, 59-68
and 71-78 for data.
Yes
Check pins 79-82 and
85-88 for data.
Yes
Check for open condition
to IC601.
No
Replace IC707.
No
Check IC602
Good
Replace IC601
No
ATSV
No
IC504 pin 20.
No
Check on replace IC401.
No
Replace IC402.
Bad
Replace IC602.
11-5
DV-550U