I found two 47 mfd 10 volt capacitors in the power supply that were leaky
replaced those and let the 620 idle for 8 straight hours...The hum is gone!!!!!!!!!! Yippieeeeeeeeeeeeeee!!!! Special thanks to Rob for the Dialstring .jpg Got it replaced as well......DC offset is 9.4mv left channel and 9.6mv right channel.......... Thanks to all who posted on this..... AudioAddict