So I picked up a Zenith Z-Note 425Lnp off ebay, which has a 486SLC processor. I can find no documentation online, but it seems the model is followed by a "120", which suggests 120 MHZ.

In any case, I had a power supply for it, plugged it in and it booted off the internal HDD to an install of Windows 95. Unfortunately, the brightness and contrast sliders were glitchy, so I had to pull it apart so I could get some deoxit on the slider mechanisms inside the display.

After plugging things back together, I pushed the power button and got nothing. I can get the 2.5" HDD to spin up on my Linux machine (though it oddly won't read the partition), so I know that isn't broken.

I did note, however, a quiet "beeping" sound coming from the back of the unit near the power plug. It's a rhythmic beeping (like it's an armed time bomb or something, lol). and it's coming from the area immediately around the power connection.

Visual inspection doesn't reveal any blown capacitors or other obvious damage. Cable connections are complete - nothing that got pulled apart which I missed.

I put my multimeter on what looks like a power regular (looking up the part number didn't tell me much, either, though), and I see rising and falling DC voltages on it... which seems like the sort of thing a power supply might do if there was a short overloading things somewhere.

Not sure where to begin...