Popped in a new thermistor and bolted up the heatsink, powered it on and I heard a ka-chunk which was the protection relay working, sprayed a noisy vol pot, did some power checks and out the door it goes.
The fans went from full on to idle speed. Hopefully they will rev up when it gets hot, I do not have the capacity on my dummy load to run 500 watts all day but it should be good.