Gregory's Serverhere's an interesting card that came in for attempted repair: a Hercules MC1024 Micro Channel video card. it uses the weird Micro Channel bus, and it is based around the TIGA graphics processor. and it appears to from the computer have been untimely ripp'd.
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i don't think there were any important components on the torn-off part. it should be fine, i'm just worried about the power plane shorting to the ground plane. the VGA connector was a bit difficult to remove but i got it out. i also removed the crystal so i could examine the clock generator chip for damage. it seems ok. i ground down the ragged edge of the board to clean it up and clear out any shorts, and verified it with the multimeter. unfortunately the card doesn't work. i think it is missing this socketed chip, which appears to be some sort of Micro Channel bus interface. rather important. i checked the power and ground pins and they don't match the 82C611/612 parts. it's something else. i did a little digging and found a photo on a German retrocomputing forum (https://www.dosforum.de/viewtopic.php?t=10607). this is the best photo i can find. i don't think this was a very common card. looks like the chip is a "DI" (?) "HCT CIA-2" hmm, even if i manage to find the chip, the other problem is that i don't have the ADF file for it. this is the adapter configuration file and it is required to get the card to function. hilariously, one of the folks on dosforum mentions that they have the ADF file, but then they don't share it. there's another chip on the board with the same logo. it's not "DI" but it is the logo for Hercules. i found a vintage ad for an older Hercules card. The LPT112 is their custom parallel port chip. no idea what it is doing on this newer video card. maybe they were using it as a GPIO port. @tubetime Almost every third-party MDA adapter I had "back-in-the-day" also had a parallel port. ... and it looks like it connects directly to a DB25 on the card, so that makes sense. @PCOWandre right but what is it doing on a Micro Channel graphics card without a parallel port @tubetime Aah, see, I wrote that reply before seeing the main thread with the MCA card. Interesting. I assume to smaller pin header on the top of the card is VGA feature; do the pins on the bigger pin set trace down to that chip? dumped the ROM onboard and found this at the end. maybe i should ask this guy lol. @tubetime I'd guess the parallel printer port chip is there so game controllers can be attached. @tubetime ftp://ftp.oldskool.org/pub/IBM_PC_BBS
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@tubetime have the same card in full working order. Would not mind making it available if you require it |
ouch.