I have two of these RX-C52's ' cause I really like 'em, but I ruined the logic control play/record functions, by attempting to adjust the speed pot on the tape motor and forgetting to unplug the machine before removing the front circuit board with the logic buttons on it. FF and REW still work. Luckily I have another good unit, so I have been swapping transistors, capacitors, diodes, ic's, and whatever those blue bubble looking things are, and after each swap from the good board to the bad board, and bad to the good board, the bad still won't work and the good one still works. I'm at a loss, here and still have more swapping to do. Does anyone have any other suggestions?