Philips DVP3550K Service Manual page 14

Disc cannot be read .
Disc cannot be read.
Yes
Check the FFC connection
between 24P and the loader.
Yes
Check whether there is laser
voltage (1.9V for CD and 2.4V
for DVD) on L101 and L102.
Yes
Check
peripheral components are
eroded or badly soldered.
Yes
Check if there is RFO signal on
pin17 of XP2. (The normal RFO
signal is a clear reticulated wave)
Yes
Check the connection
between U1
Yes
Replace U1 or loader
U1, U10, and
5-4
No
Check the loaded circuit
1. Whether voltage on pin14/pin15 of U1
varies between 2.4V and 3.3V (PIN14=2.4V
No
and PIN15=3.3V for CD;PIN14=3.3V and
PIN15=2.4V for DVD),
2.Check whether peripheral components are
eroded or defect
No
Re-solder or replace the defective parts
No
Check U1 and peripheral components
No
Correct connection
Trouble shooting chart