Spent some time with the 300 today since the 500C is now up and running
One of the HV power chokes was the culpret of all my trouble. Its fixed now. I also isolated the chokes with Rubber Vac line. Oiled and tightened the fan and cleaned the Changover relay.
Now I am back at Full power and when you key it, all you hear is the relay clicking.. No buzz at all and no chassis hum ect..
Going to install it back in the main operating position tomorrow and take the 500c down for upgrades. Good to have my old pal the Globe Champion 300 back!
Thanks to all for the help!
Clark