Don't check resistance while the circuit is powered. It supplies it's own voltage in order to take a measurement and you will damage some multimeters by doing that. But 60 milliohms is about two test leads, so that is fine it seems like a good connection.
Swap the psu if you have another known good one to test if possible. If not you need to google how to load test a psu with a dummy load or electronic load.
I suspect if that checks out then there is either a partial voltage rail short on the board which could be caused by a component, a voltage rail short to somewhere it shouldn't. Or a missing ground or another shorted component connected via the cpu.
Lots of resistance testing or when you can... socket the cpu then touch test (being careful not to burn yourself) looking for other components getting warm.
Notice he is jumping the power good - PS_ON pin in the power supply so it starts up.
I also have other AT PSUs to try. I have a ATX-to-AT connector too.
I also have other AT PSUs to try. I have a ATX-to-AT connector too.
Your 286 motherboard and AT PSU do not have a PS_ON pin.
https://pinoutguide.com/Power/MotherboardPower_pinout.shtml
I'd like to have a bordview file of some 8086/286/386 now, I'm curious to see what it's all about with motherboard design.
If the CPU is getting to 50C immediately, that doesn't seem normal for a 286.
I haven't touched one in a long time but I remember those early CPUs would only get warm to the touch, not burning hot, after prolonged use; late 486s and Pentiums is when heatsinks and fans started being necessary.I'd like to have a bordview file of some 8086/286/386 now, I'm curious to see what it's all about with motherboard design.Here's a 386: https://alexandrugroza.ro/microelectronics/system-design/isa-80386dx-sbmc/index.html
I tried the keyboard microcontroller (Jet Key), in other boards it would not work (no POST) or give Gate 20 error.
Could this be the sign of a malfunctioning of the keyb controller?