I just got a 414 and I am trying to diagnose an issue. I have found that all the functions work as expected, but when I attempt to play a tape back with the volume cranked, I can just hear a very faint crackle as if the audio is attempting to play back both through the headphone jack and RCA outputs. The record function works as I was able to record and play the tape on another device. All the lights and VU meters indicate that there is audio on the tape attempting to playback. Also the microphone is audible through the monitor, just nothing playing back from the tape. I read that there may need to be some capacitors replaced. Any idea which ones I should replace Or maybe something else going on? I opened everything up and it looks to be in pretty good condition. Any insight will be helpful, thanks!