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Thread: Wanted: Compaq Portable video card or someone to repair mine

  1. #11

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    Quote Originally Posted by VERAULT View Post
    Well you know what, if anyone has a schematic of the compaq portable 1, we can build an adapter that would give the pins requiring power from the psu and make another 9 pin adapter to connect to the external monitor out port. Shouldnt be hard as long as we know what the pins are.

    This way you can use any video card you wish. (MGA, CGA, and possibly Ega)
    I'm persuaded that most luggables used CGA cards or something close and composite monitors. CGA and MDA and EGA are not interchangeable. EGA and MDA frequencies are close though. I have a Compaq here I have to look at soon.

  2. #12
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    Yeah, I'm almost 100% sure it uses CGA, just on a set of proprietary internal pins instead of the db9 connector. I'd be going back to cga instead of trying to figure out ega. I definitely wouldn't be bothering with mda either.

  3. #13
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    I just found the pinout of the Compaq VDU card on the following thread. Correct me if I'm wrong but it sure doesn't look like cga to me. Maybe MDA but definitely not cga. I think it might be best to have the original card repaired after all.

    http://www.vcfed.org/forum/showthrea...paq-Portable-1

  4. #14
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    It is a hybrid of sorts. It uses normal CGA frequencies in graphics modes, but an MDA like resolution in text mode. That makes text mode applications look much nicer. The built in CRT monitor is custom designed to support that. A special key combination will enable CGA frequencies in text mode so you can use the composite/RGB video output port at all times to an external standard composite/RGB monitor. (There may also be a motherboard DIP switch for that, I can't quite remember off the top of my head)

    Note that you will normally get no video output at all in text mode to external monitors unless you have forced it in to CGA compatibility mode.

    Anyway, because it has proprietary features, if it is broken you will need to replace it with an identical Compaq Portable video card. Those come up on eBay every now and then when someone parts out a busted unit.

    There were only a few special third party cards that supported Compaq's internal monitor (certain models of the ATI EGA Small Wonder, or something like that)

  5. #15
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    I think I found someone that can do some work on the original card for me. Is it usually the capacitors that go bad on these? I don't see any external damage

  6. #16

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    While the issue is quite often capacitors other components may fail electronically without any visible sign(s) whatsoever. Hence, external damage is not a useful method for evaluation of a board's functionality.
    ☀☀☀ Visit Take Another Step for both computer and non-computer related discussions. ☀☀☀

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  7. #17
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    First, make sure you are not getting confused by its normal inability to output to an external monitor in text mode.

    From my own experience, usually video cards die from bad RAM (usually still operates though), or from static or voltage imbalance received through the external ports.

    In the cases I have heard of bad capacitors on a video card, that usually prevents the machine from powering up at all.

    So, in other words, I would not expect that a simple capacitor would be the problem.

  8. #18
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    I'm doubtful that one of the chips or something else would fail so unexpectedly, so I'm going to go out on a limb and get all the caps replaced. One question I do have is where I should order them, and what the codes on them mean. I have 38 labelled KIZ 473, 4 labelled 106 +16k, 2 labelled 10k, 2 labelled 18k, 2 labelled KX7R 104M 200v, and 2 labelled either R5k 151 or ASK 151 (hard to tell which).

  9. #19

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    Quote Originally Posted by RadRacer203 View Post
    I'm doubtful that one of the chips or something else would fail so unexpectedly...
    Why would you say that?

    Do you know something we don't?

    All electronic components are subject to failure. Nothing lasts forever.
    ☀☀☀ Visit Take Another Step for both computer and non-computer related discussions. ☀☀☀

    If you're looking for DS/DD or DS/HD 3" or 5" floppy disks, PM me. I've got some new, used, and factory over-labeled disks for sale.

    There is a crack in everything. That's how the light gets in. -- Leonard Cohen

  10. #20

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    I have a couple of IBM CGA cards, Both were working fine one day and dead as a door nail the next, and it's definitely not the caps, Visually they look good all over, These old electronics can drop dead at any time without notice as my trusty 5150 did a couple of days ago with psu failure.

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