Matt, When you get the time, you might want to replace the Molex female connectors. I have found that the spring contacts either weaken over time or flat out break, which means they don't make a good connection with the mating pins. Also, check for cold solder joints where the pins meet the PCB. It doesn't hurt to reflow those joints because I found a few cold joints when I recapped my Series II a few years ago. Also check the female Molex connectors where they're soldered to the board. I've seen weak joints here as well. Over time, pulling and reseating modules can stress a weak or cold solder joint enough to cause an interrmitant signal or weaker signal (more resistance due to the poor contact), so you have to eliminate these things before more troubleshooting. The good thing is that it's easy to do!
Also, Chris's suggestion about the pre-echo mute switch is a good one. Since I never use it, I just hardwired a bypass on mine. I got this tip from Steve Albini because he did the same to his Series II. Anywhere there's a connection is a chance for an intermittant, and this switch seems rather superfluous to my needs. Cheers, -- Don
