Philips PET717, Service Manual

Page: 22 / 44

5-8
No video picture, no sound.
Replace
R86,R87,R89,R90,C86,C88,C89,D14
No video picture,
no sound.
Check if the reset circuit consisting of
R86,R87,R89,R90,C86,C88,C89,D14 and
Q17 is normal (at a low level for tens of
milliseconds, then constantly at high
Check whether there is
27MHz signal output .
Check the loaded circuit
Crystal oscillator Y2 and
peripheral components
are defected or eroded.
No
No
No
Yes
Yes
Yes
27Mhz waveform
Trouble shooting chart
Check whether all the voltages
from the IC U1(OZ518) to the
decoder IC are normal.
CVBS waveform
Check if there is 135MHz
signal output on R129.
Check whether
short-circuit or bad
solder on U6,U7
SDRAM(R99 SDCLK) waveform
Check U3.
No
No
Reconnect the component in
short-circuit
Yes
Yes
Check if short-circuit and
bad solder exist on Pin 136
of U3
Yes
No