1. How can I measure the DC offset? I mean what is the procedure to do this?
2. Is there a pot o pots that I can adjust to lower the DC offset?
You need a service manual or call Krell for the procedure to do it. But maybe it is not the root of the problem.
3. Any other things I should check or do to correct this problem?
Your Krell Evo 302e amp shutts down after about an hour of use and emits a series of two red flashes which indicate there is "excessive DC out at the output". I think it is thermally
problem. My suggestion is clean all vent slots of the case and the circuit boards and heat sinks, make sure it's dust free.
If the problem still exists after cleaning, that could be signs of components start to fail, my advise is sent the amp for service before more damage happened.