Ok, I don’t know why I didn’t think of this earlier but I came up with something for the Triplett and redid the family photo. How about some rock-n-roll from my record collection?
Anyways the test setup for doing some DC voltages on the meters is this Elenco Precision kit power supply split two ways. One to feed the vintage meter under test and the other to feed an HP 3457A to observe the test voltage on since the Elenco doesn’t have any built in meters to display its output on. As for the Elenco, without any fine adjustmentS on its outputs, you guys can decide for yourselves if the Precision part of its name applies.
The Elenco bottoms out at 1.25 V according to its specs and the HP pretty much confirms that. This’ll be a safe starting voltage to apply in case a connection gets reversed by accident somehow and tries to run a meter movement backwards below zero.
First up is the Universal AVO Meter all the way from Dover, England (cue the memories of the slam door third rail trains barreling south out of London):
The 1.26 V from the Elenco has woken up the AVO and moved the pointer pretty much to where I’d expect it to be.
Running up to 5 V moved the pointer to just a hair below mid scale on the 10 V range.
At 10 V, the AVO came in just under full scale, about one division worth under, so at first glance the meter movement appears to be undamaged and tracking voltage well, at least on the 10 VDC range.