So about 3 weeks ago I got a used digitech RP80 for my birthday. Its been amazing up until two days ago. It started buzzing like hell even though the gate on it is on and functioning. I unplugged the unit and plugged it into the pedal before it (Korg tuner) and it no noise at all. I put the RP80 in bypass mode and it still makes noise. To top it all off its messing up my tone making it really muddy sounding, and it screws with the drum track sounds too. Is there a way to fix this?
Probably a dicky input jack. Those things are notorious. Is the input a bit loose on the plug? Does it come good if you hold it in a certain spot?
It is most likely the jack, or another faulty part of wiring. With how you got it, I don't think there is much you can do to get it fixed or get an upgrade. I wouldn't spend money to try to fix it, because lower end multi-effects will become more and more obsolete the more professional you try to make your music.

If you're able to, look into getting one of the RP-X55 models. I have the RP-155, and it works well. The 255 and 355 upgrades are even better and just barely more expensive.

If you don't mind the 80, just try to get a working replacement pedal. Trying to fix it might be more hassle than it's worth.
Last edited by Will Lane at Nov 14, 2014,
Can't hurt to unscrew it and take a look. Look for the obvious .. loose retaining nut or bad wire connections to the jacks.