Is this 55" Hitachi a good buy? (lines on screen)

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  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Well, for comparison, a 2006 NEC 50 incher (that I fixed) drew close to 550W full white and about half that average.

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  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    490 watt max, 393 average. I guess it could be worse for a 2007 55" plasma.

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  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    More than likely 12V for audio or main board you could run a fan off. Most Panasonics use fans for reliability. Disappointing that Hitachi wouldn't use some, especially if it's an older plasma (much higher power consumption)

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  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    I think these ICs are just kind of crappy. There are lots of people on ebay offering repair service for this board for $80-$100 so, I guess the problem is wide spread.

    Surprisingly this beast has no fans although I think it has room for some. If I get it working I think I might add some. Is there 12v anywhere on the psu I could tap into?

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  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    If they haven't bulged on this set they're OK. I think the failure on this is simply a random event.

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  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Ok, and what about the "big cap" you talked about in earlier posts? Is it on the power board? They all physically look good, but I haven't put my meter on them yet.

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  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Originally posted by mattpd
    I wasn't planning on replacing the glue, but I am thinking twice now... Is there anything I could buy locally at a home improvement store? Will these ICs get too warm for hot glue?
    Hot glue isn't great but it should be an acceptable substitute.

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  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    I wasn't planning on replacing the glue, but I am thinking twice now... Is there anything I could buy locally at a home improvement store? Will these ICs get too warm for hot glue?

    Leave a comment:


  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Originally posted by mattpd
    I was surprised to see it too. It makes diagnosing things a whole lot easier. I have opted to try to change out the IC instead of the board. I got the old one off with minimal problems, now I'm just waiting on the new one in the mail...

    I'm going to be as careful as possible and triple check my work before plugging the TV, but what if I screw up my soldering job? Is it possible it could damage other boards or even the panel when I turn it on?
    If you short lines together, you'll likely damage your new buffer IC, but that should be where the damage stops.

    The panel is essentially glass and wires. It's very difficult to break it electrically.

    Originally posted by Th3_uN1Qu3
    How did you manage to remove that epoxy? Or was it something softer.
    It just peels off. It's HV insulating epoxy. Because each of those rows are energised with -200V/+400V relative to common depending on the current state of the sustain waveform. I had one buffer with a rather toasty insect (a small fly) between some of the pins. It didn't end well for the insect -OR- the buffer but luckily the part was cheap.
    Last edited by tom66; 11-08-2012, 01:18 PM.

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  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Soft silicone I think, i just used a razor. But when encounter epoxy usually 200c from the heat gun and a razor blade will do it. What is this soft glue for? keeping the legs from lifting?

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  • Th3_uN1Qu3
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    How did you manage to remove that epoxy? Or was it something softer.

    Leave a comment:


  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    I was surprised to see it too. It makes diagnosing things a whole lot easier. I have opted to try to change out the IC instead of the board. I got the old one off with minimal problems, now I'm just waiting on the new one in the mail...

    I'm going to be as careful as possible and triple check my work before plugging the TV, but what if I screw up my soldering job? Is it possible it could damage other boards or even the panel when I turn it on?

    Leave a comment:


  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Oh, I see it! That IC has a hole in it... wow. Usually they just go on their own accord. If something was real bad, the TV wouldn't power up at all, or all the ICs would be dead.

    Leave a comment:


  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Is there anything that may have caused this IC to explode other than just old age? These boards are kind of expensive. I don't want to hear a pop when I plug it in. Should I check anything on y-sus?

    By the way the square in the middle of the right IC is hole where is failed. It's hard to tell from the picture.
    Last edited by mattpd; 11-07-2012, 09:09 PM.

    Leave a comment:


  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Reseat every connector going to the plasma panel, I have seen one bad connector on a Panasonic cause -all- the screen to go interlaced.

    Be super, duper careful with them as breaking them will make the panel useless.

    Leave a comment:


  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    I think you nailed it! This is the bottom buffer board. Is there anything else I need to check before powering on with a new board?
    Attached Files

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  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    No, the buffers control each part of the screen themselves, but when one goes bad, it can cause a problem with the -whole- of that scan. So the odd lines are energised, but the TV sustain senses that short, the TV goes blank for that field, then the evens are fine so you see all of those light up, etc. That's my theory. I've never seen a buffer line failure, only a completely dead buffer.

    Leave a comment:


  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    So instead of having a buffer for top and one for the bottom, there is one for the even rows and one for the odds?

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  • tom66
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    I have seen that both with loose buffer connections and with bad buffers. The displays on some older plasmas are interlaced. I suspect you only need to replace the one with the line on it.

    Leave a comment:


  • mattpd
    replied
    Re: Is this 55" Hitachi a good buy? (lines on screen)

    Ok, I got the tv up and running. I will try to describe the problem better. That one 1cm line you can see is the only part of the picture that is displaying correctly. The entire remainder of the screen has one horizontal line of working pixels followed by one line of black pixels and this pattern repeats all the way through. So every other row seems to be working. Still a buffer board problem?
    Attached Files

    Leave a comment:

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