I had the same problem one day was doing groceries and my trunk had a lot of stuff in it so I pinched something under the sub and low and behold it stopped cutting off I hope this helps everyone

 

I'm going to pinch something too and that might fix my head

 

Here's the actual cause of the issue, and the permanent fix.

http://forums.maxima.org/5th-generat...-once-all.html

Btw there are two separate threads on this literally at the bottom of the first page discussing this same topic. Search before starting new threads, please.