Model: 42PFL3704D/F7
Serial: YA1A********
This TV is my daughter's TV until it completely stopped working.
Initial problem: no display. If left a while and/or opened connections checked would sometimes come back on and work for “weeks.”
Then started blowing fuse F1601 as soon as power cord plugged in.
By removing R1424, R1604, and C1507, would not blow fuse. Isolated the problem to Q1602 (2SK3561) and replaced (TK8A50DA). TV has problem described below. I have also replaced Q1601 with a TK8A50DA (because it was part of the same switching circuit and didn't know if they had to be matched), but still have below problem.
Problem: When the power cord is plugged in, the TV powers up – Relay RL1201 engages and front Power Light comes on - no display. After 7 seconds, the relay drops and the Power Light goes out. The screen never shows any signs of coming on.
I have checked the following voltages at the Inverter Board. The first number is the power on voltage and the second is after 7 seconds and the relay drops:
HOT Side:
+345V: 345V – 0V
HOT +17V: 16.5V – slowly to 0V
POWER-CONTROL: .68V – 0V
HOT +22V: 19.95V – 0V
COLD Side:
AL +3.3V: 3.3V – 3.3V
AL +5.0V: 5.3V – 5.3V
PANEL +24: 0V – 0V
T1701 Terminals 10-11: 0V – 0V
T1701 Terminals 14-15: 0V – 0V
I need some help in determining where I need to test next. I am attaching schmatics.
Any assistance would be greatly appreciated.
Jeff
Serial: YA1A********
This TV is my daughter's TV until it completely stopped working.
Initial problem: no display. If left a while and/or opened connections checked would sometimes come back on and work for “weeks.”
Then started blowing fuse F1601 as soon as power cord plugged in.
By removing R1424, R1604, and C1507, would not blow fuse. Isolated the problem to Q1602 (2SK3561) and replaced (TK8A50DA). TV has problem described below. I have also replaced Q1601 with a TK8A50DA (because it was part of the same switching circuit and didn't know if they had to be matched), but still have below problem.
Problem: When the power cord is plugged in, the TV powers up – Relay RL1201 engages and front Power Light comes on - no display. After 7 seconds, the relay drops and the Power Light goes out. The screen never shows any signs of coming on.
I have checked the following voltages at the Inverter Board. The first number is the power on voltage and the second is after 7 seconds and the relay drops:
HOT Side:
+345V: 345V – 0V
HOT +17V: 16.5V – slowly to 0V
POWER-CONTROL: .68V – 0V
HOT +22V: 19.95V – 0V
COLD Side:
AL +3.3V: 3.3V – 3.3V
AL +5.0V: 5.3V – 5.3V
PANEL +24: 0V – 0V
T1701 Terminals 10-11: 0V – 0V
T1701 Terminals 14-15: 0V – 0V
I need some help in determining where I need to test next. I am attaching schmatics.
Any assistance would be greatly appreciated.
Jeff
Comment