Those with experience with Rowland Model 6's?

I have the 6's with their battery power. My whole system is Rowland.
The Coherence II, the Cadence, and the Model 6's.
Incredible with my Quads, both the 63's and the 989's.

Need help if anyone can answer....
One of the amps is warming up unevenly. The right side warms up the left is much cooler. The other amp is coming to temperature and maintanining it correctly on both sides.

Have replaced the fuses that are supposedly to maintain temperatures, on the left side of the troubled amp. But still no difference.

The amp works as well as the one that maintains its temperature on both sides.

Any ideas what might be amiss? Am I forcing the amp even if there is not audible difference?

Thanks for any help.