[Elecraft] KPA1500 Odd Happening

[w5sum at comcast.net]

just turned on my KPA1500 to check into a Ten Ten International net, and 
when I put it in Operate Mode I had a Fault light, and the displayed showed 
that the HV ( 50V ) was only 9.6volts.  I tried turning off the Amp and the 
Power supply several times to no avail. Finally I just unplugged the power 
supply for a few minutes. Plugged it back in and fired the ps and amp back 
up and all was normal. WHEW.. glad for that but.. WHY did it do this?

thanks and God bless

Ronnie W5SUM