I've got this great old big box EQ with a mains plug. Only issue is that there's no bypass indicator. I found this site with some details: http://falseelectronics.blogspot.com/2016/11/electro-harmonix-graphic-equalizer.html
Any clue where I could tap in to power a LED? Would change out the switch to make it work unless there's a more convenient way. Also -- on the site linked above, his unit came with a non-stock master volume knob. That would actually be a pretty handy add. Any clue where to stick a pot (and what might be a good value) in the output section to make that work? I'd feel more comfortable poking around in there if it weren't for the mains plug...