Hi all. I've got a LG 60PK750, which recently stopped displaying images. The television still turns on (has sound and screen lightens) but no picture is displayed.
I pulled off the back and checked voltages, and all seem in line with what's on the label.
Next I figured I'd test the logic board, so I disconnected cable P31 and joined the r51 and r52 holes with a bit of wire, before turning on the television. The TV turned on and displayed test patterns, which I kept running for a while to ensure it could be sustained.
Since it was able to display a series of images of various colors just fine when the only change I made was to the logic board (the bit of wire seemed the deciding factor, rather than the P31 unplug), that suggested to me that the logic board was the source of my issues, rather than a power or sus issue. However when I installed a replacement I had the same exact problem from the start, and when I performed the r51/r52 test on the new board it also produced test patterns.
I see three possibilities here:
1. I was shipped a faulty replacement logic board.
2. I'm a moron and the problem is actually with the board I've been considering "just the a/v input board", not the logic board.
3. The problem lies elsewhere.
I don't see how 3 is possible, given the board-isolating nature of the testing. However people here are more experienced than I am, so I thought I'd post here before throwing money at another replacement board. My gut is leaning towards situation 2.
If anyone has any thoughts or insights, I'd welcome them.
I pulled off the back and checked voltages, and all seem in line with what's on the label.
Next I figured I'd test the logic board, so I disconnected cable P31 and joined the r51 and r52 holes with a bit of wire, before turning on the television. The TV turned on and displayed test patterns, which I kept running for a while to ensure it could be sustained.
Since it was able to display a series of images of various colors just fine when the only change I made was to the logic board (the bit of wire seemed the deciding factor, rather than the P31 unplug), that suggested to me that the logic board was the source of my issues, rather than a power or sus issue. However when I installed a replacement I had the same exact problem from the start, and when I performed the r51/r52 test on the new board it also produced test patterns.
I see three possibilities here:
1. I was shipped a faulty replacement logic board.
2. I'm a moron and the problem is actually with the board I've been considering "just the a/v input board", not the logic board.
3. The problem lies elsewhere.
I don't see how 3 is possible, given the board-isolating nature of the testing. However people here are more experienced than I am, so I thought I'd post here before throwing money at another replacement board. My gut is leaning towards situation 2.
If anyone has any thoughts or insights, I'd welcome them.
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