I have recently bought a hi-quality multimeter (AVO eight, mark VI) built in
1984.

The multimeter gives low readings (-15%) on all AC and DC ranges. After many
checks, I have fully isolated the movement and I have determined that it goes to
full scale with a current of 44 uA instead of the nominal 37.5 uA. I have
carefully checked that there is no shunt in parallel.

I presume there must be some way to adjust the meter sensitivity, but I am not
sure how to do it One way could be to reduce the tension of both helical
springs, but I am afraid I would not be able to recover a 15% loss that way.

On the other hand I do not think the problem is with the magnet aging, as I have
an older AVO multimeter (model eight, mark 2) which was built a few decades
before and still works perfectly.

Morever, the question arises why the meter sensitivity has degraded.

Any help?

Tony I0JX