Hello,
Just got a Tektronix 2440 from ebay. I live in Europe so first thing I selected the proper voltage.
It ran ok for about 5 minutes and then there was a hissing noise coming from inside the scope and then some smoke.
Next second I turned it off. So I opened it up because I wanted to look inside to see what burned. It is kinda crowded there, I managed to see a slightly burned wire coming from the fuse to inside the guts of the scope.
Anyway, I decided to turn it on again but this time running at 120volts from a transformer. It ran ok, everything is good, passes all tests, it is in CAL, no errors. Hmmm...
I selected 230 volts but this time I also powered it through the 120 volts step-down transformer. It didn't start, only the GPIB Led's were blinking so I'm guessing voltage selector works.
Now it runs at 120 volts. It has been running for two days, like 5 hours a day with me near it just in case.
What do you suppose has happened? Now even the burning smell disappeared because in the first day I could feel it coming out of the vent grill...