Pentax MZ-M Woes

I took delivery today of a Pentax MZ-M (the U.S. model would be the ZX-M). I didn't really want the camera but it came with a Vivitar 55/2.8 Macro, which I did want. I put in two CR-2 batteries and tried to load a roll of film. The film would wind to the first frame and then automatically rewind the roll. When I then press the shutter button I hear a whining noise. My questions are - Am I doing something wrong? Does anyone repair these? Are they worth repairing? I have many Pentax 35mm SLRs but those, except for the ME Super and K2 are mostly mechanical. I like the idea of having a body with a 1/2000 top shutter speed (other than my ME Super and K-mount Vivitar cameras), TTL flash and higher ISO settings.

Most likely the dreaded gear issue

https://www.pentaxforums.com/forums...lp/350804-failed-mz-m-plastic-gear-issue.html

Broken mirror-return gear would be a very common problem with these cameras. I followed this pictorial guide when repairing my MZ-3, and the job was a success.
http://m.ipernity.com/#/doc/five/album/677141
MZ-M ought be be somewhat easier to fix, lacking as it does the built-in flash. Pop-up flash mechanism is also another weak area, so in a way, this lack becomes a bonus. The rest of the plastic gearing in my camera looked reasonably stout, showed no obvious signs of wear or deterioration, and appeared to be designed to operate with little or no added lubrication. So if you can fix it, your reward could be an essentially maintenance-free camera.