Its possible that the motherboard Capacitors need to be changed if they haven't been already. Maybe as the temp rises during play the Cap values fall out of tolerance resulting in locking up. There are 5 Caps on the board and may have a bloated/swollen look like me New Years day Use 10v 1000uf, 105c Caps. I know you mentioned being disconnected from the power board but when I started having issues with my game this cleared up a lot of them.