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Thread: IBM CGA card produces 1 long beep + 2 short beeps

  1. #1

    Default IBM CGA card produces 1 long beep + 2 short beeps

    Hi,

    I have an IBM CGA card that that came with an IBM 5155 that had a shorted 12v cap (marked "C8"). A common issue it seems.
    After replacing the cap the PSU kicked in again but I was greeted with 1 long beep and 2 short beeps on the 5155.

    I have a second identical IBM CGA card that does work, and the IBM 5155 starts normally with that card, so I'm guessing the issue is with the original IBM CGA card that came with the PC.

    He's what I already tried :

    • There is one seated chip on the card. I swapped the seated chips and confirm that both chips do work (on the working CGA card I can use the seated chip from the "bad" CGA card. Using the seated chip from the working CGA card in the "bad" CGA card produces the same beeps)
    • Replaced all 10uF 16V caps (none of them were bad I think except for C8, but recapped it anyway).
    • Tested both cards in an XT clone (good card also works, bad card does not display anything but does not beep).
    • Did some measurements using my multimeter (resistance / continuity) and ESR meter (in-circuit, not ideal) and don't see any difference between the working card and the bad card


    Is there anything else I can try ? Are there other common issue that one can have with these cards ?

    Besides the 10uF 16V caps I also see 2 other type of caps

    • K5M 473
    • R5M 470


    Are these also worth recapping ?

    Thx
    Retro enthousiast. Love everything < 486. Learning and sharing on my little channel

  2. #2
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    Default

    Quote Originally Posted by RetroSpector78 View Post
    Besides the 10uF 16V caps I also see 2 other type of caps... Are these also worth recapping ?
    Additional bypass/filter caps.
    On the IBM CGA card, if one is short circuit, the power supply will not start due to being overloaded.
    On the IBM CGA card, if one is open circuit, a 'no video' symptom is not expected.
    On the IBM CGA card, if one has changed in value significantly, a 'no video' symptom is not expected.

    On my IBM CGA card, a lot of the bypass/filter caps have long legs (up to 8 mm). I can see that if some of those were pushed over in certain orientations, a leg may contact the pin of an IC.

    Quote Originally Posted by RetroSpector78 View Post
    Are there other common issue that one can have with these cards ?
    In an IBM 5155/5160, one of the things that can cause that beep sequence is a faulty RAM chip on the CGA card. But if that was the case, expected would be incorrect characters appearing on the screen a few seconds after the beeps. I know that, because I simulated a faulty RAM chip on an IBM CGA card within an IBM 5160.

    Quote Originally Posted by RetroSpector78 View Post
    Is there anything else I can try ?
    A thorough visual inspection of the card.

    Does the Supersoft/Landmark diagnostic ROM display anything ?

  3. #3

    Default

    Thx for the info on the caps and the faulty memory. I hope that rules it out....

    I did put the CGA card in an XT clone, and noticed when I pull the card a little bit to the left when inside the ISA slot, that the PC boots and I see flickering on the screen (and the screen is "rotating" (dunno how to call it) from top to botton, like it is unable to sync.

    Regarding visual inspection ... nothing seems damaged or burnt ... tried to look for cold solder joints but didn't really see anything .... (but could be because I don't really have a trained eye for that).

    Don't have any diagnostic ROMs or tools to flash them ... will look into that.

    Thx for the response and tips.....
    Retro enthousiast. Love everything < 486. Learning and sharing on my little channel

  4. #4

    Default

    Quote Originally Posted by RetroSpector78 View Post
    I did put the CGA card in an XT clone, and noticed when I pull the card a little bit to the left when inside the ISA slot, that the PC boots and I see flickering on the screen (and the screen is "rotating" (dunno how to call it) from top to botton, like it is unable to sync.
    It almost sounds like the card might not be seating correctly but in this case it would because of the card, itself, and not the slots.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  5. #5

    Default

    Cleaned the isa slot contacts on the card with isopropyl. A couple of people suggested reflowing the solder joints .... Doing it manually now, although some suggested using some flux and a hot-air gun.
    Retro enthousiast. Love everything < 486. Learning and sharing on my little channel

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