Hitachi 51swx20b convergence problem


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Hitachi 51swx20b convergence problem

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steveco
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Oct 16, 2010, 8:22 PM

Post #1 of 8 (3431 views)
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Hitachi 51swx20b convergence problem	Can't Post

I have a blue halo or shadow on my screen. I did an auto magic focus and it appears to quit while aligning the blue. So I tried to do a manual alignment. The grid shows the horizontal blue lines out of alignment in an arcing fashion. Blue vertical appear fine. When I tried to move the blue into alignment vertically it would move the lines left to right just fine, but when I try to align them horizontally they will not move. Any help will be appreciated. I do have an electrical/ electronics background.

jts1957
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Oct 16, 2010, 10:29 PM

Post #2 of 8 (3428 views)
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Re: [steveco] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

Convergence ICs, check bias resistors and pico fuses (if any).

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steveco
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Oct 18, 2010, 1:10 AM

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Re: [jts1957] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

any idea as to the location of the IC's and fuses. I don't have a schematic of the tv. if I recall there are three fuses on what I'll call the power board where the incoming 120v comes in. They are all good. I don't see any other obvious fuses. There is a board at the base of each projector light and three boards behind them. Which board am I looking at. Thanks again for any info. I don't have a problem calling in a tech, but i would like to educate myself in advance, and/or fix it if I can get enough info. i work on machine toll controls, just not familiar with tv's

jts1957
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Oct 18, 2010, 1:16 AM

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Re: [steveco] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

http://elektrotanya.com/...egoria=&kat2=all

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steveco
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Oct 26, 2010, 3:13 PM

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Re: [jts1957] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

I bought a repair kit and installed the two IC's and one bad resistor. The tv worked fine for about four hours and the blue started mis-aligning. I went back and checked the resistors and found two bad that were not originally bad. I had documented all values. So I replaced them and the same thing happened as I thought it would. Worked for a while and went sideways again. What next?

jts1957
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Oct 26, 2010, 4:20 PM

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Re: [steveco] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

Did you obtain reputable name-brand IC's through a trusted source?
Did you clean the old heat transfer compound off and apply sufficient fresh?

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steveco
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Oct 27, 2010, 1:08 PM

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Re: [jts1957] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

I think I trust the chips. They were a tv-repair kit house with alot of different repair kits and service to offer. I used the new supplied goo, and I trust my solder joints, I checked everything again last night, even re-soldered the chips. I have extensive experience with control boards and connector soldering. The tv did the same thing last night, after 1-2 hours the blue started to drift.

jts1957
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Oct 27, 2010, 1:26 PM

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Re: [steveco] Hitachi 51swx20b convergence problem [In reply to]	Can't Post

What does your repair kit site say about the parts? Are they "genuine" name-brand (like Sanyo, for example)? Then again, they can "say one thing yet do another." I suspect either cheap chip or somehow they sent you a defective one.

Pg. 78 of the service manual has voltage chart for convergence ICs.

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(This post was edited by jts1957 on Oct 27, 2010, 1:32 PM)

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