I just purchased a Teac A-3440 off of ebay. I cued up a quad reel on it, and no sound comes out of the unit, at all, except for a hum when in sync mode. I have jumpers in the input/output sections for dbx encoding and decoding, since I won't be using that, so that should be bypassed. I have the outputs turned up. I have it in playback mode. No matter what I do, the tape moves, the thing turns on, but no audio will playback, and the meters won't move, not in playback or sync mode. Is there some funky setting this thing requires to work, or is this DOA?