Lrp Sphere thermal ?

[gazoff]

I am have been having trouble with my Lrp sphere, the best way I can describe it is that it starts stuttering and then stops, this is at the end of a run. Having looked on here for a solution, I think it is thermalling.

The problem seems to be that it does not recover from this, it seems to have cooled down but still stutters even after an hour or two !( it works 3 or 4 hours later when I get home ! )
I have read a post on here suggesting that once the system has thermalled then it will always be a problem, is this true ?
How long should it take to recover ? seems cool to the touch but still does not work.
Can I override the thermal protection ? ( Which wire do I need to cut ! )