I forgot to bridge it, it indeed boots up when I do, relieved I didn't fry it :) Will check J15S solder points on the core and do some more tests, thanks again! Well I managed to start the sequencer for the first time! Now it looked like it behaved like it should. Previously the intro seq took ages, and had a seemingly random pattern, and when it finally went to play the sequence, instead of going from left to right it looked like there was a mirror of the sequence going in opposite direction. Now it boots up after 5 seconds, and everything looks normal. It turns off after the slightest touch, so there's some loose contact somewhere I'm sure. Looks like I'm getting there! thanks again.