konc wrote on 2025-04-23, 09:56:
Do we know where these cards get their power from for their ISA part? Could it be the -5V pin? I can't think of anything else that makes sense after reading what OP has tried.
I have that card as well. I guess half of the retro system builders on VOGONs have a copy of that card. The card is a 5V only design, both for PCI and for ISA, so missing -5V is not supposed to hamper ISA operation. As the OP clearly stated that the LEDs are lit, I guess we can safely ditch the theory of the card being plugged in the wrong orientation. When using the card on the ISA bus, you should be aware that the LED labels are not accurate. The -5V supply lights the 3.3V LED (as there is no 3.3V supply on the ISA bus, it makes sense to re-purpose that LED), and the FRAME and IRDY lines are some ISA activity lines. IIRC someone posted on VOGONs which ones, i think one is /MEMR to indicate access to (ISA) memory, with the intention to show access to the BIOS ROM, and the other one might have been /IOW.
Thus, on an ISA system with this card, you expect all 4 voltage LEDs to be lit (no 3.3V if -5V is missing), the CLK LED to be permanently lit, the RESET LED to be lit for a fraction of a second after power up, and also during press of the reset button, and FRAME/IRDY happily flashing during POST. Also, you expect some POST codes to appear.
I can't come up with a reason why the cards are not working on multiple ISA mainboards. It's not impossible that these cards are now produced with a different firmware than the earlier look-alike cards, and the new firmware doesn't work on ISA. On the other hand, having cards both with the Atmel and the SyncMOS microcontroller with both not working makes the "new firmware" theory unlikely.