Supply hasn't got much to do with how hot the box gets: two disks and not a lot of ventilation does, however.

I'd suggest looking at the ventilation around the sled. If you over-cook the empeg, then like any other electronic device that's thermally stressed, eventually it will fail. Make sure that there's a good through flow of air for the player, or space around it for convection.
_________________________
One of the few remaining Mk1 owners... #00015