Re: Craigslist: JCM 900 $200, needs work?
From my experience with JCM900s and dirty pots, you'll probably need to replace a few. They're pcb-mounted too so it's kinda a pain. If you have good desoldering skills, it's definitely do-able though. You might get lucky and be able to get by with just a good cleaning but I've had two come through here and both required replacing pots.
As the seller says, it's a bit of a leap of faith. If it really is just the pots, I'd consider doing it. However, I'd definitely want to listen to the amp before making the deal. For all you know a transformer may be dead or some other issue that would suddenly make it not worth the investment. Also, the tone of the post comes off a little "smarmy salesman" to me, and that sets off some warning bells IMO. I mean he doesn't even say which model JCM900, and if he honestly thinks any of them are the greatest amps of all time, to me, that makes the rest of what he has to say suspect.