Regarding RFI.... I also have a Miller Sync 250 in my basement shop. My house has AT&T "UVerse" that supplies high speed internet, TV and Telephone service to my house. When I start to weld in DC, the high frequency arc-start system runs until I get an arc.... and shuts down my UVerse ...

Hi Steve,

You wrote... "O-ring lubricated in the back-cap? "

Is there any special lubricant that should be used? Or can plain oil or Vaseline be used.... sparingly?
(Newbie TIG welder here, reading a lot and trying to learn.)

Thanks,
Dan