Sick Agilent U1252B

[wizard1]

Back in July I acquired a new old stock Agilent U1252B from Nmori87. Everything looked good with my limited initial testing, but I've since discovered that it shows incorrect values in the DC 50V range when used with a shunt type RF probe. Initially I thought it was the probe, but I have confirmed with 3 other meters (U1252A, Fluke 87 V, and cheap Radio Shack portable) that the probe is working correctly. I have various supplies around the homelab and everything I've thrown at the faulty U1252B does show the value I would expect (again confirmed with 3 other meters) so I believe it's more than just an adjustment to calibration constants.

I've reached out to Keysight for help but of course the meter despite being new is out of warranty. I assume repair is going to be more than the meter is worth, are these repairable at home? I haven't yet been able to locate a schematic. Does anyone have experience with repairs on this meter?