7-20
6. H OSC / DEF / HV CIRCUIT FAILURE
Check the drive pulse at CN-DSB pin 10 on the DEF PWB (PWE-
568) outputs a rectangle waveform which amplitude is 4.3Vp-p.
OK
Normally, it is sawtooth wave which amplitude is
approx. 5Vp-p.
NG
OK
Be sure to get the L5G2 off the DEF PWB, and
output as following.
NG
Note: Q561, Q5G1 and Q5A1 will short out at the same time.
OK
Measure the voltage at Q553 collector.
Normally, it is approx. 15V.
NG
OK
Normally, its amplitude is approx. 50Vp-p~60Vp-p.
NG
OK
Measure the CRT anode voltage.
Normally, high voltage is approx. 27kV.
NG
Measure the voltage at CN-P pin 3 on the SW/HV PWB
(PWE-571).
CONTINUE1
CONTINUE2
CONTINUE3
approx. 220V
Horizontal period
Check the horizontal drive pulse.
Check the waveform of IC592 pin 3.
IC592 or its ambient circuit failure.
Check the waveform of gate at Q5G1.
Q5G1, ZD5G1, D5G2 or their ambient circuit failure.
Check the voltage for horizontal drive circuit.
R557 failure
Check the AFC pulse at R5E1.
Q555, Q561, T551, T561 or their ambient circuit failure.
Check high voltage.
Check 80V line.