Hi all. I have a cycling and screeching Samsung plasma that I have found described many times with various fixes. To be more descriptive, about a year ago, it started taking two or three tries to start. Last month, it was up to about a half hour of cycling on and off with various rainbow snowy pictures and screeching noises. By Thanksgiving, it would not start at all most of the time, but every now and then it gets lucky. If it does start, it's good until it is turned off.
Model : PN58A550S1FXZA
Logic Board : BN96-07703A
Power Board : BN44-00183A
When I started, I found all the bad cap threads and thought I had the golden fix. Sure enough, I started removing caps from the power board to test with a calibrated LCR meter and they were pretty degraded. I replaced all the caps for the low voltage supplies, but I left the high voltage caps alone because my HV test points were right on when measured and I read somewhere that the low V ones were the more common failures. I also did not replace a bunch of caps on the hot side of the hot/cold divider line because they measured okay. I was disappointed that this did not fix the problem.
I then found a thread where someone with this same problem re-flowed the logic board and fixed it. I re-flowed mine and it didn't change, but to be sure, I ordered a replacement logic board... and it didn't change.
So back on suspecting the power board, I re-checked all the voltages coming off the four output connectors. I have verified the following...
VS 202V
VA 65V
VG 15V
Vamp 18V
D5.3 5.3V
12V
I had previously inspected for cold solder and bulging components on the power board and nothing jumped out. Before I started posting this, I figured I should give it another thorough look since I see that pictures are normally requested. Okay, so none of the solder on this thing would pass inspection where I work, but I don't really think that any of it is bad enough to cause this either. But, maybe I should take it in to work anyway and re-flow everything I can just in case.
So, assuming that my re-flow attack doesn't work, where do I go next? I know you'll probably want pictures, but my camera batteries aren't holding a charge and I don't have a smart phone... so it may be a day or two on that.
Thanks.
Model : PN58A550S1FXZA
Logic Board : BN96-07703A
Power Board : BN44-00183A
When I started, I found all the bad cap threads and thought I had the golden fix. Sure enough, I started removing caps from the power board to test with a calibrated LCR meter and they were pretty degraded. I replaced all the caps for the low voltage supplies, but I left the high voltage caps alone because my HV test points were right on when measured and I read somewhere that the low V ones were the more common failures. I also did not replace a bunch of caps on the hot side of the hot/cold divider line because they measured okay. I was disappointed that this did not fix the problem.
I then found a thread where someone with this same problem re-flowed the logic board and fixed it. I re-flowed mine and it didn't change, but to be sure, I ordered a replacement logic board... and it didn't change.
So back on suspecting the power board, I re-checked all the voltages coming off the four output connectors. I have verified the following...
VS 202V
VA 65V
VG 15V
Vamp 18V
D5.3 5.3V
12V
I had previously inspected for cold solder and bulging components on the power board and nothing jumped out. Before I started posting this, I figured I should give it another thorough look since I see that pictures are normally requested. Okay, so none of the solder on this thing would pass inspection where I work, but I don't really think that any of it is bad enough to cause this either. But, maybe I should take it in to work anyway and re-flow everything I can just in case.
So, assuming that my re-flow attack doesn't work, where do I go next? I know you'll probably want pictures, but my camera batteries aren't holding a charge and I don't have a smart phone... so it may be a day or two on that.
Thanks.
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