Here's an album of images. Not actually a camcorder, but it uses a standard Hitachi camcorder mechanism. Specific camcorders that I believe have the same mechanism are the Hitachi VM-3100A and the RCA CPR-250.
https://imgur.com/a/ZcX3P
I'm gaining confidence that it's down to a hard pinch roller, so I've ordered a bottle of Rubber Renue, and will be giving it a try once it arrives.