Re: LG 60PZ750 running hot and maldischarged
Board still the same....I had a good friend who is an audio tech come over last weekend and check it out with me and there was no change in the wave form when we were testing. This could be because the board now acts maldischarge right away when I turn on the TV. The one thing I did notice a few times that is very strange is when the TV has been unplugged for 30-45 min and I put the board back I do get a small arc on one of the ground screws, this appears to happen when the screw driver touches the black heat sink and ground screw while installation (see pic). When I do the bub test with this board the buld are brighter than a good board that has no issues so that makes me that there is slight bleed to ground ? When the board is in without the bulbs it will not blow any fuses....I even went as far as replacing all the fgpf4633 IGBT transistors again in case I had a defective one. Below is a recap of what I have done so far.
Tested and Replaced all fgpf4633 transistors twice
replaced all gate resistors that were blown, tested and all read 13.5 Ohms in parallel.
Resoldered inductor coils twice, second time I even bridge the solder to the closest pads beside the coil points in case the the tracing was bad.
Resoldered the C142 small cap that is on the same trace.
touched up all solders on the heat sinks that looked poor.
Board still the same....I had a good friend who is an audio tech come over last weekend and check it out with me and there was no change in the wave form when we were testing. This could be because the board now acts maldischarge right away when I turn on the TV. The one thing I did notice a few times that is very strange is when the TV has been unplugged for 30-45 min and I put the board back I do get a small arc on one of the ground screws, this appears to happen when the screw driver touches the black heat sink and ground screw while installation (see pic). When I do the bub test with this board the buld are brighter than a good board that has no issues so that makes me that there is slight bleed to ground ? When the board is in without the bulbs it will not blow any fuses....I even went as far as replacing all the fgpf4633 IGBT transistors again in case I had a defective one. Below is a recap of what I have done so far.
Tested and Replaced all fgpf4633 transistors twice
replaced all gate resistors that were blown, tested and all read 13.5 Ohms in parallel.
Resoldered inductor coils twice, second time I even bridge the solder to the closest pads beside the coil points in case the the tracing was bad.
Resoldered the C142 small cap that is on the same trace.
touched up all solders on the heat sinks that looked poor.
Originally posted by tom66
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