hey, glad to see this thread up again. It's not over til it's over. Let's add a couple hundred more posts.
Does the bass control add and take away bass on RF? How about the loudness control? Since it is just one channel, I would bet on perhaps, somewhere in your recap you replaced a signal path cap that was 1/10th it's supposed to be value, like a 0.47 where a 4.7 needs to be. that's the one I and my son are most likely to make mistakes on. But look for the simple things first.
You could swap the inputs going to the OP driver boards and see if it follows the input wires, or the 2624 boards. If it's on the 2624, that should be pretty easy.
Maybe you have a bad meter. Hard to test when it's all assembled. I just changed a meter bulb with the front panel on, so it can be done. With your multimeter, see if you can put the probes on a meter that is working and get a reading. If you can, try it with the bad meter, so you'll know if signal is getting to it or not.
It's pretty normal to get a thump when you switch to 2X, did it play in that position? there's not much likelihood of blowing anything up. Usually it's the switch contacts, because that position is little used. If it doesn't work at all or one ch doesn't work, and it's not the 2X switch, there's a relay on the bottom board behind the front panel that controls/reroutes the signals in 2Xmode. I take all the relay covers off and clean and lube them as part of what I'm doing. the relays are pretty much unobtanium, although you could buy a 4pdt 24vdc relay and wire it to the pc board.
So, have you checked out the, ahem. . . . new 9001? does it work? have you re-pinned the 4 ch board yet? :yes: I'm jealous...... of course.
