AVO Multimeter survey

[Jennings]

Originally Posted by The Philpott

Post no. 3317
Jennings, the Model 48A uses a 1.5v rectangular cell which is obsolete, although on ebay you may find a replica Ever Ready adaptor which an enterprising bod has 3D printed and added a genuine looking label, designed to house a C cell. I bought a couple recently.

I may have a DC shunt for the Model 48A, if you can post a pic of the one you have i'll see if i have 'the other one'.

Dave

Thanks so much info and tip off...those are great looking adaptors, so I've ordered one accordingly.

I've attached three pictures of what I have in the Admiralty type set, Looks like I have the two pictured shunts (I have yet to stabilise the asbestos insulator layers) and the current transformer, but I'm missing the multiplier which consisted of some glass tube resistors in a ventilated wooden casing - picture four shows what I'm missing. Although they appear very aged/perished the set does appear to contain period test leads and clips...and the case also doesn't bear the ID plaque. In fact doesn't look like it was ever fitted with one (no holes for fixing pins or screws anywhere). So perhaps a surplus or un-issued set?

[The Philpott]

Multiplier wound with super thin wire, ah yes, my mistake.

Don't leave any old rubberised test leads in the box as they leach sulphur into their immediate environment which can blacken silver contacts inside the meter.

The asbestos on the DC shunts (we assume it's asbestos) seems quite tough and non-friable unless it's actually had an impact.

Dave

[Sinewave]

Originally Posted by greenstar

I found this lovely Avo at the Bring & Buy, Biggleswade, last Sunday. it appears to be an original Avo (Model 1?), which came out in 1923.
Despite my best efforts the photos do not show the small lettering on the scale, which is,
B.S. First Grade. No 135940.
Any information would be welcome. This one appears to be working. It is a little disconcerting, as the meter damping is not at all the same as the 7's and 8's I have. Measuring 11volts, the needle swings over, bounces off the stop, and comes almost immediately to rest. at 11. I would like to use this, and am guessing that it's sensitivity is less than the 7 or 8?

Wow what a find.

Hopefully one day I'll add one to my collection. It's pretty much the only one I need in my line up.