RCA VDT-350 Playback Issue

[TinCanAlley]

The head was a bit dirty on the unit, so I ran a cleaning tape through it, as I've done a number of times before, but this time something went wrong. I don't know if the issue was caused by the tape, or was going to happen anyway.

The issue is playback speed. The playback is about 1/4 normal speed, then goes back to normal, then back to 1/4 and back again. Sometimes it stays slow for a minute or so before going back to normal and same for normal speed. I would think it something with the speed selection, but this thing is not auto speed, you have to switch it. Also, there is only two speeds and no extended play.

So I'm not sure what it could be. It might be a belt, but I don't know if a belt issue would cause a slowdown that still produced a visible picture. That and I've replaced all the belts and idlers about a year ago. Heck, I don't think there's a rubber belt or tire that I haven't replaced.

This thing has been great up til now. I want to fix it. I have the SM for it, but it doesn't address what I'm experiencing.