Over the last couple of days my TS-520SE blew its final tube cathode resistors three times. Digging into the issue with help from the guys at the KENWOOD TS-520_820_530_830 yahoo group I found that the probable cause was that I was running GE JAN 6146W tubes which are not recommended for use in the Kenwood Hybrids. I replaced the resistors and switched back to my original S-2001A tubes that came with the rig. Will see if that fixes the problem. :) Maybe the S-2001A’s are good luck cause the first contact was CO2VQ/QRP in Cuba.