I just unpacked and powered up a new E3647a and it has an unusually loud mains hum... akin to a cheap florescent light fixture (ie. with a poor ballast). That is with the outputs off. When under load it changes somewhat but not significantly. Definitely sounds like transformer noise / vibration. Otherwise, all else seems to be ok.
It is many times louder than my Rigol DS2072 scope, my laptop, or anything else in my office for that matter. Is this normal?
Thanks,
Andrew