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Another silly symcure

Discussion in 'Electronic Repair' started by [email protected], Apr 13, 2007.

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  1. Guest

    OK, sitting here trying to print the print for this Toshiba that is
    being stubborn, I gave up. Disgusted, I purged all print jobs. Fukum,
    print it at work. In fact I just unplugged the printer.

    My latest folly into the twilight zone was that the set came in with
    basically no convergence correction, scoping the outputs and checking
    the supplies revealed nothing. The convergence output board was simply
    not being driven.

    Well, one audio IC later the set is fixed.

    This is an ITC222 52". We know the audio is not tied to the
    convergence.

    Well, I learned something that day, the audio IC's heatsink is not
    ground. Funny, I was trying to keep it away from the power board lest
    a hot and cold heatsink touch.

    What is really wierd is that it blew the audio IC, not anything
    pertaining to the power to it. It went into the three strikes mode.

    Nice how they do that isn't it ? It was just a matter of two heatsinks
    touching, in an terrible servicing environment that THEY created.

    Now remember, I found no bad components either on the convergence PS
    or the output board. There was no significant offset on any of the
    outputs. Nothing.

    So then I fired the set up with the audio PS plug disconnected. Now
    the convergence is fine.

    It has fired up multiple times just fine and I'm shipping it. The only
    thing I can figure is that there was a data error somehow and the set
    basically forgot it was an RPTV. Everything else was fine.

    So that's an actual symcure, if all is well except convergence, find a
    non-destructive way to make the set shut down and go into three
    strikes mode. Somehow it defaults, and the convergence was perfect,
    well really good. Didn't even have to set the center.

    Really, all that requires is to short out one of the supplies, even
    off the flyback. You might get that done without even removing the
    board.

    Of course software problems can be addressed with a PC, but we don't
    have the newer interfaces, and we are reluctant to upgrade because
    these things are such a piece of crap.

    I would almost rather work on an Apex RPTV or a Akai/Samsung. But I
    said almost, it is pretty much a tie at this point.

    BTW folks, BEWARE that the Akai/Samsung units have high current focus.
    A shorted CRT socket blows the FCB (or sixpack) really fast. Look for
    those coolant leaks. That causes it.

    In fact on all RPTVs, look for coolant.

    So anyway, I know these manufacturers are trying to drive me crazy,
    but I got news for them. It is too late.

    JURB
     
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