I have owned a Fender Bassman 100 combo amp (15" speaker, not the newer, smaller one) for several years; it's been wonderfully reliable until the past few months. It still works fine 80+% of the time, but I've been having 2 related problems: 1) Often when I turn it on, it won't make a sound until I play really hard on the bass -- then a huge pop and the sound comes through ok. It will usually play fine for 30 minutes or so after that, then the sound will start dropping in and out (similar to when it's turned on, including pops). 2) Half the time the sound is coming in and out, there is also a nasty crackling, almost as if the speaker's blown -- though it's not, for once the amp works properly again, the speaker's fine. The "signal" light on the front of the amp still lights up when I'm playing the bass and the amp's not making any sound. Could it be dirt or is it an electronic problem? I've cleaned out the input jack half a dozen times by now, but I haven't cleaned the pots yet; it's hard to believe it could be related to the pots but I could be mistaken. It's driving me crazy, as it happens quite randomly and is really hard to track down. I've tried multiple cords, basses, etc., with the same results, so I'm pretty sure it's the amp. I found a post from March ("Bassman 200 woes") that sounds similar -- the diagnosis was the input jack & capacitor soldering. Could this be the problem on my Bassman 100 as well? Please help -- thank you!