Thank you for your responses.
Are you certain when you put the 5x86 back in, you had it positioned correctly in the socket?
Well, I took extra care this time, but in retrospective it's hard to tell. Now given I did put it in the wrong way, the thing broken should be the TIP107, right? (And eventually the CPU I guess.) Given that I didn't put it in the wrong way, what else could have caused the TIP107 to overheat like that?
I had the same problem with my LS486E mainboard, I have no experience with electronics so I just use 5V cpus or 3V with adapter.
I thought about that too, unfortunately these boards are quite rare and really expensive, so I figured I'd go with soldering a cheap replacement transistor. Well, lesson learned, kinda.
If you have followed the manual, then most likely the manual are wrong on the FSB settings.
On my board, it is "reversed" from what is explained in the manual. I have had help on Vogons before.
But that should only apply to the FSB right? Which shouldn't cause the TIP107 to overheat, just general CPU malfunction of some kind, I presume.
Regarding the TIP107, are there any heatsink on your's?
I put the heatsink of the original TIP107 on there. I instantly burned my fingers when I touched it and the TIP107 had bubbles on its surface when I removed the heatsink. So I don't think that was a problem of the heatsink, it definitely became much too hot for 4 or 5 seconds of normal operation.
Well I do have the impression that in case I did not put the CPU in the wrong way there might be something else that's faulty. I'm thinking about measuring the voltages at the TIP107 mounting holes, I feel like there's something wrong. Do you got any other ideas?