I just bought an old Portastudio 488 for a low price. Unfortunately the machine had been gathering dust and gave me some crackling switches, pots and faders.
So I boldly unscrew it and detached all PCB's to service the moving parts with some contact spray.
Most mechanical parts are doing fine now except one cue switch and the master 3/4 fader. The switch might need some extra spray, but the fader could be broken. The right channel keeps disappearing till I move it sideways. I checked the soldering which looks OK.
Are there known issues with these faders?
Are there some faders for sale?
Are there some geeks that love to see the inside of a 488? I'll glad to post them!
I don't know what type are in the 488, but I've taken faders apart to repair them when fader cleaner wasn't enough.
I use a small jewelers screwdriver to pry them open (lift the metal tabs from around the plastic bottom section). You will sometimes find bent or weak contacts, so you have to gently bend them back into place to line up with and have enough tension against the carbon tracks.
Most recently I've done this on an old Moog synth.
Yep, you could get that open, possibly even without desoldering it from the board (though that might be awkward). I start with the tiny screwdriver to get the metal tabs up far enough to finish bending them straight with a small needle-nose pliers.
Don't jab yourself in the finger with the screwdriver (I've done that). I keep my tetanus vaccination up to date.
After jamming the fader with a coin during recording, I was so tired of losing the signal more and more. I Finally decided to take the Portastudio apart and repair the problem.
I expected to find a internal broken pot, but by examining the PCB, I noticed there was only a loose solder point. The microscopic small crack was at first to small to notice, but became more visual by the jamming with the coin.
So 1 minute soldering and 10 minutes to open and close the casing and the problem is fixed!
