[Boatanchors] d'arsonval meter question

[E C Moxon]

Hi all.
I've got an old hp 723a supply whose meter movement seems to be out of
whack. The meter housing has been busted for many years, but the movement
seems to move smoothly, no sticking. Its just that the deflection is about
12% low on all 3 voltage ranges (seen at midscale, fullscale). The
multipliers are all measuring better than 1%

So the question is, what kinds of things would account for overall reduced
sensitivity? It's a 1-mA 50-ohm movement. I'm not too hopeful that it will
turn out to be anything I can fix, but I'm curious.

Ed, K1GGI