i picked up a portastudio 424 mkii through craigslist last week, and i'm having a few issues. the first is scratchy knobs in the mixer (often on pan, trim and effect2/mon). using a contact cleaner/lube product, i was able to clean up a few of them which was good, but a few are still being stubborn so it looks like i will have to disassemble this soon for a more thorough cleaning. some of the knobs have a dark gunk underneath them when i pull them out. is that some sort of rust? has anyone done this sort of process before?
a bigger problem is that the fat pitch knob does not settle into the 0 setting very tightly. that means a slight nudge could make the tape go up in speed. how is this going to be fixed?
here is a weirder problem - overdubbing onto track 3 sometimes works, and sometimes doesnt. and finally, there is sound bleed from previously recorded tracks, even when the faders are down to 0 (i mainly heard this from 3/4).
a bigger problem is that the fat pitch knob does not settle into the 0 setting very tightly. that means a slight nudge could make the tape go up in speed. how is this going to be fixed?
here is a weirder problem - overdubbing onto track 3 sometimes works, and sometimes doesnt. and finally, there is sound bleed from previously recorded tracks, even when the faders are down to 0 (i mainly heard this from 3/4).