"Patrick Turner" wrote in message
...
There should be no DC current flow into the CT on the OPT for
about 8 seconds after turn on when the amp is cold

So I don't know why you are measuring 190mA flowing into the CT at switch
on and
then seeing it drop back to 170mA.

You may not be measuring the current at the right point.

There may not be anything wrong with your amp.

You say there is B+ drop from 480V to 440V over 1.5 hrs.

But does this drop occur after 20 seconds? if so, the amp is OK,
but if the B+ starts at +480V at after say 30 seconds, then very slowly
falls
40V after 1.5 hrs,
something is causing it.
It's never happened in amps I have built or serviced.

During initial turn-on, the current meter shows 0 as you mentioned. It will
slowly reach 190mA after 30 seconds or so. At this point, the voltage
measured is 480VDC. The drop occurs gradually over a period of 1 hour till
1.5 hours.

The Amp meter is fitted between the output of the power supply and the input
supply to the amp.

Regards,
Mark