Sharp SX80J9, Service Manual

Page: 16 / 68

16
SX80J9
16-2 16-1
Circuits to be checked:
• PIF circuit.
• A/V circuit.
• Video output.
• Peripheral circuit of Bus Line.
Normal
No snow noise.
Check pin (21) of IC201.
Abnormal
C
Noise or signal
appear.
Is AV1, AV2 or AV3
input normal?
Check Q205, Q215, Q212,
Q213, Q214 and their
peripheral circuit.
Check PIF circuits
and its related parts.
Yes
No
Check (36) of IC451
NOISE or signal
appear?
Check IC451 its peripheral
circuit.
No
Yes
Check pin (2) of
IC802 noise or signal
appear?
Check IC802 its
peripheral circuit.
Check IC801 RGB
out Normal?
Check IC801, their
peripheral circuits.
Check the
peripheral circuits
of screen heater
(FBT) and the CRT. Check Q850,
Q851, Q852 and
their peripheral
circuits.
Yes Are collector waveforms of
Q850, Q851, Q852 normal? Yes
No No Yes No
Check TU201, IC201 etc.
Does 5V appear at pin (7) of
TU201.
Check L201,IC606 etc.
No
Yes
NO PICTURE
Circuits to be checked:
• A/V circuit.
• Tuner.
• PIF.
• Peripheral circuit of Bus Line.
Does the snow noise appear
on the picture tube at max
contrast and brishtness
control?
C
Snow noise increase.
Does 9V appear at pin (6) of
TU201 (TUNER). Check IC601, TU201, IC201
etc and 9V-2 line.
Yes
No
Does 33V appear at pin (9) of
TU201.
Check IC203, TU201, L200
Yes
No
Does 12V appear at collector of
Q201.
Check 12V line IC602 etc.
Yes
No
No
Yes
TROUBLE SHOOTING TABLE (Continued) TROUBLE SHOOTING TABLE (Continued)