TV was on and suddenly went dark with no sound and led started blinking twice which according to the service manual, is the G6 power supply board (PFC, 3.3V STBY and 12 volt regulated). It also has a G8 board that is the LLC resonance circuit board and provides the 24V regulated. This board still was providing the 3.3V STBY, of course since I was getting blink codes and also the AC off detect 3.3V.
I ordered a NEW board (not Ebay) and when I installed it, it did nothing. No picture, sound and no voltages except AC to main rectifier and a rectifier output that is low but no DC outputs. Assumed I had gotten a bad board and returned it for a new one and it did exactly the same thing.
When I put the original board back in, it still gave the same indication of 2 blinks and standby power available. I started measuring around and found the R6540 resistor/fuse was blown. It is just before the circuit branches to feed some more circuits that eventually provide some of the 12V regulated outputs and the PFC out that feeds the G8 board. I hope to replace the resistor/fuse and install the G8 board and hopefully this will not just the board again because one of the other boards besides the G8 board is actually causing the problem
I have the schematics but they are in the service manual that I have and the size is 18MB so I'm not sure if this site allows uploads that big.
This G6 board has outputs the aforementioned G8 bard as well as to the BATX (main) board and the T-CON board and I hope these boards aren't the ones with the short.
I am hoping someone is knowledgeable about this setup and has some warnings or checks I can perform. I am not very familiar with switching power supplies and it seems weird to be doing DC measurements on circuitry feeding a transformer but I guess that's the only way you get a reading of that high frequency chopped signal (at least that's what I remember is occurring).
Right now, I have the G6 board isolated and am making the measurements with no connection to adjacent boards.
I have looked at the caps and they don't have visual signs of failure and after looking closer, I did actually see some staining by that resistor/fuse that blew.
I ordered a NEW board (not Ebay) and when I installed it, it did nothing. No picture, sound and no voltages except AC to main rectifier and a rectifier output that is low but no DC outputs. Assumed I had gotten a bad board and returned it for a new one and it did exactly the same thing.
When I put the original board back in, it still gave the same indication of 2 blinks and standby power available. I started measuring around and found the R6540 resistor/fuse was blown. It is just before the circuit branches to feed some more circuits that eventually provide some of the 12V regulated outputs and the PFC out that feeds the G8 board. I hope to replace the resistor/fuse and install the G8 board and hopefully this will not just the board again because one of the other boards besides the G8 board is actually causing the problem
I have the schematics but they are in the service manual that I have and the size is 18MB so I'm not sure if this site allows uploads that big.
This G6 board has outputs the aforementioned G8 bard as well as to the BATX (main) board and the T-CON board and I hope these boards aren't the ones with the short.
I am hoping someone is knowledgeable about this setup and has some warnings or checks I can perform. I am not very familiar with switching power supplies and it seems weird to be doing DC measurements on circuitry feeding a transformer but I guess that's the only way you get a reading of that high frequency chopped signal (at least that's what I remember is occurring).
Right now, I have the G6 board isolated and am making the measurements with no connection to adjacent boards.
I have looked at the caps and they don't have visual signs of failure and after looking closer, I did actually see some staining by that resistor/fuse that blew.
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