Alright, some strange behaviour.
First i checked the voltages without the 6080, i got these: 71, 231, 0, 231, 68 (for 1 to 5). I checked the TIP50s and the heatsinks, seems like nothing is touching there.
Then i noticed that some of the LEDs weren't lit: the one between the center terminal and A8, and two on the big speedball board at the back. So i checked for shorts a bit, saw something maybe a bit suspicious between A8 and A9 so i moved A8 a touch (edit, A7 and A8 actually). Powered the crack back on after this and i saw/heard a bit of a spark within the 6080 tube. Checked voltages again after this and suddenly we're back to normal - from what i can tell all of the voltages are fine now.