A quick look at an HP3455A voltmeter, along with some preliminary troubleshooting, due to the unit being faulty and the seller having reported a bang and smoke last time it was switched on.
I should have mentioned in the video that error 11 refers to cal constant #11 being out of acceptable range. A future repair video of this unit will go into more detail on this error code.
There will be future "quick and dirty" teardowns , and repairs, of some other pieces of equipment that I have, including more HP devices.