9
Open pin 3&4
of Q862
B+ to low
Open fuse F470
Main B+ is below
150V. Freq. at pin 14
if IC801 is above 60Hz.
Main B+ goes to 155+ then
to 0v Relay stays on. Frquency at
pin 14 of IC801 is 60Hz
Open F470
Problem is in the load.
Short pins 3&4
of Q862
Problem in the feedback loop.
Recommended checks: Z801,
and Q862
Open pin 3
of Q862
Problem is in primary side of power supply.
Recommended circuit checks: IC 801,
Over Current protect and Oscillator
Problem is in primary side of power supply.
Recommended circuit checks: IC 801, and
Oscillator
Push power button
Does the relay engage?
No
Check: Sub Power supply, Microprocessor
and Relay drive circuits
Does the TV go into
shutdown?
Yes
Yes
No
Is the B+ at F470
Low or at 0v?
0V
Check start up voltage and 165V on IC 801.
If missing Check F860, D801 SR81 and
surrounding compnonets.
If 165V and Start up
are present.
Power Supply Troubleshooting Guide.
Main B+ is 140V
150V. Freq. at pin 14
if IC801 is 136KHz.
Main B+ reaches 155+ the
to 0v Relay stays on.
Frquency at pin 14 of IC80
is 60Hz
Main B+ goes to 155+ then
to 0v Relay stays on. Frquency at
pin 14 of IC801 is 60Hz
Main B+ is 140V
150V. Freq. at pin 14
if IC801 is 138KHz.
Problem is in primary side of power supply.
Recommended circuit checks: IC 801,
Over Current protect, Oscillator, Latch Delay,
LC Resonance, DriveCircuit, and Pre amp.
