I checked out some of the forums on here and didn't see anything specifically related to my issue, if there is, please fwd me to it and apologize if I doubled a thread.. Anyways, I got a vintage MXR 114 10 band graphic equalizer from a garage sale. Paid $10 for it. My dad had one back in the day so I know about it. It was in pretty bad shape, the slides were all caked with junk and seized. I took it apart, deoxit'd it, lubed it up cleaned it up and it does work. I have it going to a tape monitor input and when the monitor is on there is a horrible feedback/high pitch squeal going back to my speakers(music muted). But when I shut off the monitor( or unplug the mxr) the prob goes away. I've tried the mxr on a carver amp, a sony es amp and my kr-9600 amp and its doing it on all of them. Even my wireless mouse causes some weird feedback into my speakers when this thing is on. Is there anything I can check out inside this thing or something I should be looking at. I've tried diff amps as I mentioned, diff patch cords and it's still doing it. I even remember my dads 114 doing the same thing, but not nearly as bad as this one. Any help is appreciated. Thanks much!!