I can't answer the electrical questions. But, I have an m1.0t and several m1.5t's. All have been refurbished/upgraded by Nelion to mkII status. None of them get hot at all in any place... they all run fairly cool even if driven hard (I've measured them running hard at warmest spot on the chassis and I get about 95 deg F). I have fans, but I don't use them. As long as you provide enough space around the amps, they stay nice and cool.
The m1.5t MkII's I have are different sounding than the m1.0t MkII......But, by just a bit. Not really all that different. If I had to characterize it, I'd say the m1.5t's are "brighter"...ie a little more high end. Kind of like the difference between CD's and Records, when CD's first came out... The m1.0t mkII is a little "warmer" sounding. When I pair my m1.5t's with speakers that have a lot of high end, it can feel kinda harsh on certain songs. But, really, like I said, this is nit picking differences. I've run them back to back on same speakers in blind tests, and I really can't tell them apart that easily. (Note: I had Nelion upgrade the m1.0t to MkII Opt 2, which gives it almost as much power as the m1.5t mkII refurbishment).
Hope you figure out your issue.... lots of help here on the Carver Site. Oh, and welcome aboard!