Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
Hi,
I have run a lot of scopes with the ground hot as you mention (the
scope is grounded though the AC line Ground so you need to defeat
that). The scope chassis and all adds a lot of capacitive loading
to the circuit which may very well be bad for gate drive
measurements. Also, the scope's power supplies are still referenced
to ground through the AC lines. The isolation at that point is not
very well guaranteed. So scope loading and isolation from the AC
line are issues. Tektronix scopes seem to be the "luckiest"... Dig
through the specs sheets where they give clues about how hot you can run.
........
Cheers,
Terry