My first guess would be corrosion or possibly a broken solder joint in the audio out jack. You could try cleaning the audio jack with some Deoxit or tuning knob cleaner.

If it's not one of those, then my next guess would be a faulty component in the right channel of the audio circuit.

Shponglefan wrote on 2024-05-13, 23:22:

My first guess would be corrosion or possibly a broken solder joint in the audio out jack. You could try cleaning the audio jack with some Deoxit or tuning knob cleaner.

If it's not one of those, then my next guess would be a faulty component in the right channel of the audio circuit.

Sounds good. I checked continuity from an audio cable to pins on the back of the card, and it's good for ground, left and right so I think the jack is solid. I'll try to trace back some of the circuitry, but it's dicey w/o a schematic 😮

I think this card suffers from bad caps, but I've never seen a mixer reporting 1 channel only. Check this thread on info about the caps: Audio problem with Ensoniq S-2000

Rawit wrote on 2024-05-14, 07:09:

I think this card suffers from bad caps, but I've never seen a mixer reporting 1 channel only. Check this thread on info about the caps: Audio problem with Ensoniq S-2000

Cool thanks for the link! Agree about the caps on this board, they've definitely leaked. I don't see any major damage yet, and it's hard to tell ofc. Will look more into that.

In the meantime I installed the card in a known good motherboard from a gateway E-3000 running win3.1, installed 3.1 drivers. Same issue only one channel active.

Using the jumpers I tried base/midi ports 320,330,340 & 350 as well as wave ports 534, 608, E84 & F44. No change in audio output each time I re-configured the driver.

I'll keep grinding ... 😜

I recapped this card and that didn't fix the issue (which is very frustrating as you know haha) so I started poking around on the board. After some time I located the DAC chip and accompanying datasheet. To my relief the L & R signals were present on the DAC, so the disconnect had to be somewhere between it and the audio jack. I began tracing the signals and discovered they run down the line of components mounted horizontally on the board (see red boxes below in the image.) Mysteriously the signals stopped after C78. It took me a while to narrow it down, but the VIA to the left of C78 had degraded / cracked, no longer conducting between the components. I soldered a tiny bodge there, and the channel started working. The VIA was right next to one of the leaking caps, so there you go.

Nice that you got it working!