You may not be experiencing arcing in your oscopes. An extremely common
problem with the kikisui is bad solder joints on the power supply board
where the connectors are soldered on the board. Retouch all the
connector solder joints and you should be good to go for another 8
years. I work in a Navy cal lab and have repaired numerous COS6100M's
over the years ( we had well over 100 of them, now replaced with
Tektronics 2246's), they would come in for repair due to
intermittent/jittery traces.
MKil...@exis.net