[Elecraft] KPA500 Will Not Start When Pushing the On Button

[Amateur Radio Operator N5GE]

This is a 240V Amp.

When pushing the on button on my KPA500 the power will not come on.

It worked very well until I moved it to another place on the OP Table.
and connected it to K3 #1055 after having #1055 brought up to the
latest version at Elecraft.

I have checked the fuses and verified that the power cord is supplying
the proper voltage to the amp internally and externally .

What is the most likely cause of failure to get power to the amp?

Which components should be checked next?

Thanks in advance,

Amateur Radio Operator 
N5GE

I have been up to see the
Congress and they do not
seem to be able to do
anything except to eat
peanuts and chew tobacco,
while my army is starving.

Robert E. Lee