Killed my A500. No lights when power on

A500 Rev 3 (rocklobster)

Was working. I plugged in a floppy from an A2000 to replace the broken A500 one. Now no power light, no caps lock lights, no blinks, etc.

Tested the power supply with volt meter. Getting +5, +12, -12. When I plug the power supply into the A500, I get mV reading on the +5 trace on the bottom and about 1V on the +12 trace. So something is draining / sinking the voltage, whatever you call it.

I would appreciate any ideas where to start troubleshooting.
Ordered an untested/probably broken A500 with no power supply for parts, so I can't test right now by swapping parts. Trying to buy another A500 with power supply.

Trying to learn more about 80's electronics, so would like to work on repairing this

Thanks

[dirkies]

Had this too when trying a kickstart switcher. The unit remained absolutely dead when switched on, no lights nor sounds nor hum. Removing this ks switchboard made it alive again. So perhaps take out the ks chip and see what it does.

Hi. Thanks for the reply. It appears it was the power supply. 312503-01. Converted an old 230W ATX power supply and get the WB screen again. So even though the power supply had the correct voltages being output, it wasn't even enough to power a bare A500. I don't understand power supply internals enough to know what was happening. Definately not going to open it up and play around with it. The internal fuse looked in tact. Nothing else looked burned or bulging. Maybe I'll see if it can power a car light bulb off the +12v.

At least now I might be able to power my Supra Drive. Still testing. Still have to put everything back together. Gotta make a book disk with some drivers somehow.

Thanks again.