I have completely re-routed the HV cables and sleeved them with teflon tubing, also changed the metering wire and ALC wire that was close to the HV. Still the same problem, a large snap/pop when I go from CW to SSB. Still unable to see where the arc is even in a very dark room. Could it be one of the capacitors is breaking down internally? Would you be able to hear it inside the can?