@bktemp: Thanks for the info. You mean the two "RIFA" caps, right? Yes, I will change them, especially I am soon moving back to Europe, and my plan is to modify the 3478A for usage at 240V/50Hz. And under the assumption that this caps see then more stress I guess most likely the will fail fast.
I think the line voltage change should not be a big problem: If I am not mistaken there is a cable inside the unit which connection is changed to tap to another transformer winding). What I am more afraid of is that when I set the DIP switch line frequency setting from 60Hz to 50Hz that maybe the ADC changes its behaviour slighlty, and that then maybe a recalibration of the unit would be needed. Could this happen?
@helius: Thank you too for the information about the batteries. I was not aware until now that the SAFT battery is using different chemicals than the Panasonic BR type one. It seems I do not know
much about this topic
Do you also think my battery on the picture posted above was manufactured in 1991? If so I definitely have to change it.