I'm completely stumped with this. the symptom is a small popping sound akin to the soft pops on a record album.
not a overly loud pop, but def enough to bug me.
I thought i fixed it, when after opening it and spraying it out (the pots are somewhat sealed, CTS i think, normal pc mounted) checked/cleaned connects/inputs, and found broken solder joints where the large diodes had been trimmed. they had almost imperceivable rings around them, that would open when pushed from the other side. i of course re-soldered, and touched up some pads that were light.
i didn't want to do too much shotgunning, for fear of not knowing what the fix was, and was happy when after closing it and power up it sounded fine. I played for 6 hours with no pops, and for a little bit the next day.
you guessed it! its back, after a couple days, i kicked it over and popping was right there within seconds. I've been looking into learning/getting a scope, but all i have are multi meters, a dead bug type sig-gen, bad eyes, and some decent magnifiers.
I had expected to find bad joint, or bad cap in the typically seen 4700@50V electros. I would have just changed them, but no longer have most of my parts.
all I can think of now is heat related (big jumps from inside air conditioning to outside hot) along with I just stopped playing after a few hours and thinking back on it, I didn't notice any popping towards the end, or while idling when done.
UPDATE...it made the sound while unplugged from any input. also it made/makes the sound while on battery power, or while plugged into wall wart. I've usually run it with effects from outboard multi-fx into whatever input I'm using, but noticed a noise similar, if not exactly alike, while turning pot associated with onboard fx. when changing fx, it makes the sound alike, whether the send/amount pot(s) are all up, or down. If i can find footswitch, i'll try to defeat fx, and see if it goes away.
while assembling it back I noticed speaker connects at speaker were less than stellar, but not falling off. If i had not put away the station, I would have fixed 'em better, and will when i'm back in.
any help, similar experiences?