dirty heads?
 

usually run tdk tapes but recently ran 5 sony tapes through the pd-170. a few days later i switched back to the tdk's. horrible audio drop out when played back. sounds better in a friends camera, mine sucks now. tried a tape cleaner and it hasn't helped for either tape stock. this camera is less then a year old with low run time on it. can the heads get dirty that fast or is it the tape switch? anyway to fix it without sending it in? thanks felipe

Try running the tape cleaner a few more times for no more than about 5 seconds per run and 1 minute between runs. Any longer than that or more frequently and you stand a chance of melting the goop onto the heads. When that happens it is new-head time.

The tape switch seems to be the proximate cause of the problem.