I’ve wired an appropriate size DIN connector to an ATX motherboard power extender, and soldered the PSON line on the extender to a ground wire so that it will run. Plug it in, and my Compact XT does power on.
I don’t get any video display. I’m unsure if my modern(ish) TV is incompatible with a composite CGA signal or if it’s just not outputting anything. I have an RGBI CGA to VGA converter on the way, so I’ll try that and see if I get any video. If not, I’ll have to do some further troubleshooting.
I neglected to plug the speaker in before I covered up the spot where the header is with RF shielding, so there aren’t any POST beeps.
With a boot disk inserted, I hear the floppy drive working but it’s been so long since I’ve used one I’ve forgotten what a healthy one sounds like. The disks are old. It was a new old stock set of 360k MS DOS 4.01 disks. That’s old enough that it’s entirely possible the disks are just no good anymore, especially if storage conditions haven’t been ideal.
When the converter comes I’ll resume troubleshooting. If I get video output, hey, good, I’ll get to work on the disk drive. If I don’t, I’ll open her up again, look for blown caps, bent pins, RF shielding bent out of shape to cause a short, that sort of thing, and make sure the speaker gets plugged in so I can get POST beeps to aid further diagnosis if needed.
I will expend significant effort to get this thing running again. We had a family computer before this, but this was my first computer. Nostalgia factor is high here.