HP 3468A owners UNITE: a storm is coming! But together we found the solution!

[Stray Electron]

One thing that I notice, and I can't remember if it was always like this or not - if I power it on and leave it with the inputs open, the displayed voltage creeps up... and up... and up...  Placing any sort of rational (well, I only tried up to 10Mohm) resistance across the input stops that entirely, and it registers 0.00000V. I believe this is a common occurrence, but, as I say, I can't remember if mine used to do that or not. It would be interesting to know if it is related to leakage somewhere, and if anything can be done to minimize it. In the meantime I'll just leave my leads shorted .

   Yes, it's normal for the 3468 display to creep up when nothing is connected to their inputs. I have several and I KNOW that several of them do that. But can't recall if they all do since I haven't used a couple of them in a long while.

[iDevice]

As far as I remember, the two lowest ranges are >10G input impedance, then it goes down to 10M, so accumulated gate charge is to be expected.