Hello Ken & Linda,
I had a similar problem on my Frister + Rossmann Cub4 just last week when I tried to sew some face masks (...I rarely use my sewing machine since a while). In spite of googling & searching on YouTube, I wasn't able to find any answers to my problem, so I decided to try and see if I can trouble shoot the problem myself.
Please excuse me if I do not use the right term/naming conventions in my explanations... but the important thing is that I managed to fix the problem on my sewing machine & maybe your problem is the same as mine.
My other problem was how to open the right side cover without breaking it in order to have a look at the belt/belts...
I eventually discovered that, apart from removing the screw on the base/bottom of this side cover, there are 2 very tiny screws on the top corners of the side covers that need to be unscrewed ever so lightly in order to release them (do not remove them completely!). The cover comes off very easily, & you will then be able to see if the 2 belts are in place.
On my machine, the top belt had come loose and a kind of round plastic disc that kept the belt in place had broken off. Hence, even though I had put the belt back into place, with every full turn of the wheel the belt disengages itself. The needle moves up and down as long as the belt was in place, so I knew that my 'needle not moving' problem & the strange noise was due to the disengaged belt. Both the belts were still in good condition even though I had bought this machine in 1976!
I solved the problem of the belt falling out by using some rubber plumbing washers to put on the outside of the gear to replace the broken plastic 'disc'. I managed to find some with the same inside diameter & placed 2 of these to prevent the belt slipping out. I used 2 washers in order to give it some thickness so that it will block itself in place on the cover.
On the cover, one can see the round shape dedicated to this gear 'space'.
I then put the machine on its side, with the belt end side facing upwards, in order to be able to put the side cover back in place without the temporary washers falling out.
Once the bottom screw is in place & the 2 little screws on the top corners are tightened, the cover appears to block the washers in place, hence stopping the belt from falling out.
That works for me & I am able to use the machine now without any problem. I also took the opportunity to clean out the machine & oil it. The vacuum cleaner & a paint brush did a very good job!
By the way, although the booklet describes how one removes the base cover, it is not very clear nor correct...,
So, in case you can't figure it out, the bottom cover comes off by removing:
- The 2 screws from the left side (where the brown foldable flap is)
- Same kind of screw on the bottom (Don't unscrew the rubber 'legs/support').
- Tiny screw that is near the feed dog lever. (This screw was not mentioned in the book when describing on how to remove the bottom!)
- The screw on the right base of the side cover.
Good luck & I hope you succeed to fix your machine. It's a little gem.