Got it for free on marketplace because it stopped working after a storm.
When I began troubleshooting the power supply, I fried 2 fuses and a mosfet by shorting 2 pins on accident, but I've replaced those components.
The tv had a soundbar connected, which was also killed by the storm. On the tv side I found a transistor shorted on the hdmi 2 (arc) and a lot of capacitors shorted on the main board.
Disconnecting and reconnecting the psu to main board cable, while still being connected to 120 V AC, would wake things up, such as a red light from the optical port on the original motherboard and the cpu would begin to warm up.
When I first plugged in the replacement main board there were no signs of life. But, I removed the cable going from the psu to main board and reconnected which turned on the led indicator. I tried powering on but nothing happened.
Here are my steps troubleshooting the power supply per LG service manual.
2. PWR-ON Check : P201
- SET On : above 3V
- SET St-by: OV
***** 3.3 V *****
3. 12V Level Check : P201
- SET On: 12V
- SET St-by : 7.8V (swing between 7V to 10V)
***** 11.9 V *****
4. DRV_ON Check: P201
- SET On : above 2.5V
- SET St-by : OV
***** 3.3 V *****
5. T-CON 23V Check : P204
T-CON 12V Check : P202
- SET On: above 23V / V12V
- SET St-by : OV
***** 12 V TESTS AT 10.9 V *****
@@@@@***** 23V TESTS AT 0.6 V ***** @@@@@@
12VM -> 10.9 V
20VS -> 18.2 V
PWR_ON -> 3.3 V
DRV_ON -> 3.3 V
DPC -> 0 V
ACD -> 0 V
12VT_ON -> 3.4 V
Are the DPC and ACD voltages supposed to be 0 V? Is the 12VT_ON supposed to be 12 V instead of the 3.4 V? The service manual has those 5 steps and doesn't mention these 3 in them.
As you can see theres very low voltage at the 23 V line for the panel. So will I need to buy a new power supply board?
Thanks guys, I know this post is all over the place, but I tried my best to show what I have found so far.
SERVICE MANUAL
https://lgparts.com/products/oled77g...39678104535219
When I began troubleshooting the power supply, I fried 2 fuses and a mosfet by shorting 2 pins on accident, but I've replaced those components.
The tv had a soundbar connected, which was also killed by the storm. On the tv side I found a transistor shorted on the hdmi 2 (arc) and a lot of capacitors shorted on the main board.
Disconnecting and reconnecting the psu to main board cable, while still being connected to 120 V AC, would wake things up, such as a red light from the optical port on the original motherboard and the cpu would begin to warm up.
When I first plugged in the replacement main board there were no signs of life. But, I removed the cable going from the psu to main board and reconnected which turned on the led indicator. I tried powering on but nothing happened.
Here are my steps troubleshooting the power supply per LG service manual.
2. PWR-ON Check : P201
- SET On : above 3V
- SET St-by: OV
***** 3.3 V *****
3. 12V Level Check : P201
- SET On: 12V
- SET St-by : 7.8V (swing between 7V to 10V)
***** 11.9 V *****
4. DRV_ON Check: P201
- SET On : above 2.5V
- SET St-by : OV
***** 3.3 V *****
5. T-CON 23V Check : P204
T-CON 12V Check : P202
- SET On: above 23V / V12V
- SET St-by : OV
***** 12 V TESTS AT 10.9 V *****
@@@@@***** 23V TESTS AT 0.6 V ***** @@@@@@
12VM -> 10.9 V
20VS -> 18.2 V
PWR_ON -> 3.3 V
DRV_ON -> 3.3 V
DPC -> 0 V
ACD -> 0 V
12VT_ON -> 3.4 V
Are the DPC and ACD voltages supposed to be 0 V? Is the 12VT_ON supposed to be 12 V instead of the 3.4 V? The service manual has those 5 steps and doesn't mention these 3 in them.
As you can see theres very low voltage at the 23 V line for the panel. So will I need to buy a new power supply board?
Thanks guys, I know this post is all over the place, but I tried my best to show what I have found so far.
SERVICE MANUAL
https://lgparts.com/products/oled77g...39678104535219
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