I have a DP-03 SD that has one dead channel-the "A" input which also serves as the guitar/line/internal mic input is completely dead. all other functions are working properly. The "A" input internal mic works, as does the "B" channel. I've disassembled it to inspect the input jack and slide switch for this input and all appears intact-the unit is relatively new. i am not the original owner and I suspect some sloppy previous owner somehow managed to fry this input with a mismatched or overdriven guitar input. Any advice on schematics or which specific chips to check and (maybe) replace myself. I have electronics and music instrument repair experience. I have repaired at the component level. Thanks.
