Have a look at
http://www.jnsforum.com/index.php/topic,155.msg618.html#msg618On a side note, my M250 currently gets extremely hot even after short periods of running. I've ran it for many hours after converting it without problems and without it running hot, but when I tried it again recently, the motor and the metal frame were extremely hot. Not sure what the cause is.
Martin I was looking at your M250 and noticed it had a short or potential short on the black wire. When I first read this I though it would be some kind of floating ground that would cause this type of problem and saw this. The black wire is worn along the block.
This is old and I don't know it you found this already.
Inobu