got an ancient 80gb backwards compatible ps3 wont power on
no lights and seemed dead.

I swapped the power supply and plug and tried to fire it up. nothing

than I stuck a disc in the drive and the drive took it in.

So it looks like the drive gets power but nothing else works.?

not sure what this means yet.

cant take disc out to recreate situation without tearing the drive apart.

looking for ideas based on this info.

want to fix due firmware likely being very low for hacking purposes.

Do you get any red or yellow flash lights?

No lights. Powers on by drive fan works. No audio video.

Sounds like GPU issue anyway... need to be reflowed. In rare cases can be the southbridge, but don't think so.