RCA VDT-350 Playback Issue
 

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.

The speed is still a servo system feedback timed off the linear control track of the tape...If the head for the control track got dirtied by the cleaning tape it could be causing your issue.

I will get my hands on a different cleaning tape and do it again. Hopefully dirt is the issue.

Don't waste your time with "cleaning tapes", particularly for tape path parts. You can do a MUCH better job yourself with IPA and a swab.

You want a chamois stick or a lint/snag free synthetic material for cleaning the actual video heads.

I have some MG Chemicals isopropyl alcohol spray for electronics. Can I spray the head, or should I spray some into the cap, dips the swab and then clean the head?

If I had a product like you have, I'd spray it directly of the heads, then polish them.
I spray the cleaner directly on the video head pole pieces. Once in awhile the tiny gaps get plugged with oxide. :scratch2:

Okay, the spray and cleaning swab worked like a charm. However, there's a new issue. I'm going to open another thread to keep on topic.

Thanks for all the advice.