I had same problem...playback on old tape shows gray lines on view screen. Cleaned head(s) with rubbing alcohol. No Change. Put in new tape and recorded for 30 seconds and playback was fine. Put in old tape, same problem. Rewound to beginning of tape, recorded for 30 seconds, playback was fine...problem gone. However, I think I will have it professionally cleaned just to be sure. I will use it to transfer tapes to digital. Update (07/31/2016): BTW, the camcorder is a SAMSUNG SC-27 MiniDV.