My trusty FM has developed an annoying fault. You can wind the film on without pressing the shutter release - meaning I get through more film than I want... No other faults it seems and nothing seemed to cause it. I also notice an FM2 on ebay has the same problem.

So, is this fault common, would it be straight forward (ish) to fix? I've had the bottom off my FM2 to free a stock wind on mechanism (had mirror glass in it - nothing to do with me), and I am (without being modest...) generally very dextrous and mechanically minded (all car work,other mechines, circuitry etc.). I know to be gentle and clean, but is this a job for a camera repair shop. It doesn't owe me much, and I like fixing things so would like to try it but not sure where to start.

Any help or suggestions would be very appreciated.
Thanks
Harry