Wolf Larsen
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Apr 30, 2020, 3:16 AM
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Samsung Plasma PN64F8500 Sound But No Video
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I've been working on fixing my 64" Samsung Plasma (PN64F8500). The issue occurred over a period of 6 weeks or so. Started with requiring two cycles of turning on and off the tv before the Samsung "Smart TV" logo would appear. The number of times we had to go through the cycle became more numerous. What we noticed was that we could turn the TV on without video and at some point (15 - 30 seconds later) the sound would come on without the video. Eventually (a week ago) there was nothing we could do to have it display video. At the same time, I noticed that response to the remote was similarly delayed. Turning the TV off required waiting the 15 - 30 seconds. The standby led would blink and it would recognize the remote button push, but would not turn off immediately. I've been watching youtube videos on DIY fixes since before the situation became hopeless. The one that seemed most relevant to my situation was this (https://www.youtube.com/watch?v=HNzpnnlkiV4). As opposed to the guy in this video, I found no "main logic" board on the f8500 (I can't find a schematic but I found the f8500 has more than one logic buffer boards but I can't identify which boards those would be). In the hopes that the issue existed with the "main board", I purchased the BN94-06205C from tvpartstoday. Prior to purchasing a replacement I looked at the board and could not find any components I would be able to fix. I also used a multimeter to investigate the hmdi ports (there was another youtube video that demonstrated this) but could find no issue. I replaced the main board today and the problem I detected persists. I have a solid standby led, I can turn on the tv, I get no picture, there is a delay before I can turn off the tv and get the solid standby led again. I have reviewed all the capacitors on the y sustain, the x main and the power supply boards. I see no raised or bubbled capacitors. So I've come here to look for guidance. I don't own an ESR and it seems the only way for me to use a multimeter is to desolder the capacitors I want to test. I'm prepared to buy an ESR if advisable along with the tools to solder and desolder components. My questions include: 1. Does the gradual degradation of the tv's behavior suggest an issue with a capacitor? some other component? 2. What should my next step be in diagnosing and fixing my tv? Is the Y sustain the likely culprit? the Y buffer boards? the logic buffer boards? 3. Is there a way to rule out or narrow down which component(s) is/are at issue? I'm not sure what I can do with my multi-meter and how I can establish the y sustain, x main or one of the buffer boards is my problem. Thanks for your help. I hope I was clear and not too wordy. Joseph
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