Yep, I've been using old flash gear for many years so know all the rules...this was just me struggling with a multimeter and stupidly forgetting its a BAD thing to re-fire it a bazillion times in a few seconds...

Anyway, yes, you're right - I'm pretty good with my soldering and know some basic electronics, but don't really consider myself savvy at fault finding with stuff like this.

I could possibly do the caps myself, but not keen to touch the rest.