CECH-3001A - Red power light turns off shortly after being plugged in

My problem was originally as such:

• I plug in the PS3.
• The red power light turns on.
• I press the power button. The PS3 beeps.
• The fan spins up; the power light turns green.
• After a few moments, both the fan and the power light turn off. Pressing the power button does nothing. I have to unplug the machine and leave it for some time in order to get the power light to glow again, and still I’m unable to power it on.

So I opened up the PS3, cleaned out the dust, and poked around the power supply (as I read that could be the issue). That didn’t help, so I tried using an ATX PSU to power the PlayStation. I still had the same issue as above, except when the fan and power light turned off, I was able to press the power button again to get the power light to turn back on to red.

I don’t recall exactly what I did, but at some point, my issue changed to the following:

• I plug in the PS3.
• The red power light turns on.
• After a few moments, the power light turns off. I don’t have a chance to attempt to turn it on. As above, pressing the power button does nothing, and I have to leave the machine unplugged for a bit to get it to light up again.

Trying to use an ATX PSU after this would still have the same effect; the power light would turn off when I try to power it on, then back on when I press it again afterwards.

So I threw the PS3’s logic board in the oven at 380 degrees Fahrenheit for 10 minutes, in a sorrowful attempt to reflow the board. After reassembling the machine, I ran into the same issue as directly above — once. I haven’t gotten the power light to turn on since then.

Note that I’ve tested the machine with another PSU, and still ran into the same issue. I’ve also tested the PSU in another PlayStation, which turned on just fine (well, this machine actually has the YLoD, but that’s because I messed up the NOR flash… long story). I’ve also tested multiple power cables with multiple outlets, of course.

Any help would be much appreciated. Feel free to ask me to clarify anything.

EDIT: The other PSU I tested the CECH-3001A with was from a CECH-2001B, which I now realize may have been a bad idea.