So I screwed up while making some hardware changes and trying to debug an issue with a compact flash adapter, and accidentally powered on the machine with the Clear CMOS jumper set in the clear position. Now the machine will only start up with the jumper in that position or removed, if I set it to the standard position there's no video signal at all and no POST beeps. I've tried all sorts but can't work out a way to get this thing back to life. I could source another motherboard but I feel like there must be a way to resurrect this thing. Presumably the CMOS itself is in a bad state.

I've run the IBM diagnostics (with the jumper in the clear position) and it found nothing wrong, and I flahsed the BIOS too on the offchance it'd help. I can't change the jumper while the machine is powered on, it locks it up immediately. There's one socketed chip on the board that I assume is the BIOS.

Anyone have any bright ideas?