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CapZ
Joined: 13 Aug 2009 Posts: 9
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Posted: Thu Aug 13, 2009 7:52 pm Post subject: JVC GM-V42UG plasma monitor problem |
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Hi all. I'm new to tv repair and plasma/lcd technology. However I know my way around pc motherboards, so I figured I would try to fix my plasma tv before scrapping it. Someone gave it to me. It's been used since 2004, not sure how many hours on it.
The tv turns on fine and I'm not getting any error lights. The problem I'm having is with the picture. The best I can describe it is it's jumpy and the colors look psychedelic. I have the parts list, no luck with service manual.
A quick look at the insides show no blown or bulging capacitors. Is there any way to tell which board may need replacing? Thanks in advance for any info. |
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Justmanuals
Joined: 21 Aug 2004 Posts: 1948
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CapZ
Joined: 13 Aug 2009 Posts: 9
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Posted: Fri Aug 14, 2009 10:42 am Post subject: |
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I ordered the service manual, thanks for that.
Before I start chasing my tail, can anyone give me an initial diagnosis based on the limited info I gave? Will the fix entail replacing a board, a semiconductor on a board, the screen is gone, etc.......
I'm not asking for a book length step by step troubleshooting lesson, I can figure that out and get the necessary tools myself. Just a quick "most likely culprit" hint would be much appreciated. Thanks! |
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CapZ
Joined: 13 Aug 2009 Posts: 9
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Posted: Fri Aug 14, 2009 11:19 pm Post subject: |
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I don't know how I missed them but I found 2 bulging high voltage caps on the power supply board. I didn't know they were blown until I compared them to the other two high voltage caps with flat tops. Curiously, the service manual has wiring diagrams for every board except this one, so I don't have part numbers. They have written on them "Samwha 450wv, 330uf, 105 degrees C". Think those could cause my problems above?
I guess it wouldn't hurt to change them out for a few bucks and see what happens. Is there a best brand I should get to lower the chance of this happening again? Thanks. |
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minnie
Joined: 18 Aug 2005 Posts: 2880 Location: Hell
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Posted: Sat Aug 15, 2009 1:26 am Post subject: |
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450 volts @ 330 micro farid 105 degree temp rating. |
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Guest
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Posted: Sat Aug 15, 2009 10:41 am Post subject: |
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geez, 48000 members here?! |
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jts1957
Joined: 24 Nov 2008 Posts: 2476 Location: Far, Far Away
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Posted: Sat Aug 15, 2009 8:18 pm Post subject: |
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Not all of them are here at the same time! |
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CapZ
Joined: 13 Aug 2009 Posts: 9
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Posted: Wed Aug 19, 2009 12:40 am Post subject: |
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I found a picture of the board online. This board is selling for $180, but the same caps that were bulging on mine also look suspect on this one. I wonder if someone can look at this and give me an opinion on these capacitors. They're the two large ones, center top of the board. Compared to the ones on the left, they don't look healthy.
http://photos.discount-merchant.com/photos/1013/photos.php?itemid=1049312 |
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vtech
Joined: 08 May 2006 Posts: 1264 Location: USA
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Posted: Wed Aug 19, 2009 1:40 am Post subject: |
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Having seen it before, I can tell you that they are OK and more likely the same with the capacitors in question on your board.
The subject of "bulging capacitors" is indeed valid and rather a common failure however, it is mainly observed with lower voltage capacitors and while possible, it is rare with the main filters. Only when you can see &/or feel the actual distorted metal(usually w/a cross mark burst open or about to)
In this case, what you are looking at is actually a plastic cap that is used in packaging on some of the higher voltage electrolytics. It is simply held in place by the plastic wrapping around the capacitor and often distorts and gives the similar appearance of a bulging cap. It can easily pop out and serves no real purpose other than may be isolation.
So to be sure, you can easily press against it as it will give or even remove it to see the metal underneath. |
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Guest
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Posted: Wed Aug 19, 2009 11:47 am Post subject: |
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Thanks for the info. I guess the problem lies elsewhere. At least I get to practice soldering. I already desoldered and pulled the old caps out. I'll put it back together and post a pic of what the screen looks like. I'm just not sure what board to troubleshoot. |
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