Super hot chips are usually dead chips. That said, with the Atari one common culprit is a bad power supply — certain models are known to go bad in a way that results in excessive voltage at the socket, which can easily fry multiple ICs on the motherboard.
So first step would be to verify the power supply is good (preferably by not connecting it to another machine!) Use a multimeter to check for steady 5V on the relevant pins. Note this diagram is viewing the socket, i.e. the back of the plug.
If the power supply is dead you can actually power these things from a USB wall wart if you put a cable together, I've even run one off the TV it was connected to!
Once that's been verified as good you you need to work out what else might be wrong. An oscilloscope/logic analyser is one way to do it, but far easier (especially if it's a socketed machine) is to swap ICs with a known good machine.
I had a machine that only showed dark red, and although this commonly seems to be the RAM or the GTIA, for me it just needed a replacement CPU which I managed to source easily enough online. Good luck!