jesolo wrote:By running Debug.exe, I just get two zero's.
That's good, there is something there driving the bus, otherwise it would be FF. If you want, I can give you info how to test the OPL chip timers. But many games detect presence of OPL by timers, so if any game detects OPL chip, it appears to work on the bus side.
jesolo wrote:
On this particular sound card, I can't seem to find the YAC512 DAC.
It's U5, right on top of 7805 regulator.
jesolo wrote:
I can see some of the traces of the OPL3 flowing to the MIDI synthesis chip (the one in the upper left corner of the picture).
Which ones? I only see the that the 8-bit data bus does go toward the CDROM connector. The OPL3 digital audio bus must run under the card towards the 7805 regulator, where they come to top side of the card and go up towards YAC512.
jesolo wrote:
I suspect that maybe the DAC is being shared between the OPL3 and the MIDI synthesis chip?
In some sound cards yes, but highly unlikely, as I see the YAC512 DAC, and the NEC 6376 DAC (U10) sits right next to the ATZ3310. Besides YAC512 has so weird data format no sane chip would ever output it 😀
jesolo wrote:
Since my MIDI playback is generating sound, it's probably the OPL3 chip that is dead or, some of the traces are not functioning properly.
Maybe I should heat flow the card?
If that doesn't work, then maybe swop out the OPL3 chip. However, I will have to get someone who is more skilled with this type of soldering.
Don't heat flow it, don't swap OPL3 chip. If your car does not start, would you swap the engine first, and then check if something else is wrong if it still does not start? I'd rather buy the card from you than let you ruin it 😀