Tena Koe, greetings from NZ.
I have inherited a rather nice multimeter from, I guess, the 1940’s & it’s branded University & 944 - I guess that’s the model number, & at the bottom it shows RADIO EQUIPMENT P/L SYDNEY.

I think it’s beautiful!

I tested it by trying to read the mains (230V like you guys) & it barely managed a reading of 100V.
Is there a circuit diagram for this & would some kind radio guy be able to share with a desperate Kiwi please?

Best, John😼

Circuit diagrams for meters can be rare. Photo may be useful. There may be capacitors in it and in AVO 7x, Peak meters, & others, I have found plenty faulty.

One hopes that was on the AC setting. Its liable to have a metal rectifier of some sort which may have failed. I usually open them up to assess what's in there & any signs of tampering and corrosion etc., before applying any voltage.

I do make money out of exuberance. Like power it to see if it works, often killing it.

Ohh yes, it was in the AC mode😄 & I did a careful inspection. I’ve emailed a snap to Brad.

Those old meters of which I have a few types are also very prone to verdigris etc and that type of brass etc. does need cleaning. Kevin Chants site has some limited University info. Circuitry in many of those is quite basic & easily but tediously, reverse engineered.

Do not under any circumstances, attempt to measure the resistance of the meter movement with a multimeter on ohms. You will likely destroy it.

Photo is uploaded.

Early on in my now-long career as an electrician we were told - never leave an analogue multimeter alone without first switching to AC volts. The main reason was that older meters didn't have a power switch, so the task did two things - ensured that no-one used the meter and accidentally put the OHMS or AMPS ranges into a GPO and also to conserve the internal battery.

Mind you, that didn't stop me destoying my $35 analogue Jaycar meter about a year ago - I had been using it all morning and forgotten to change the range and up in smoke she went. Fortunately, Chinese-made off-the-shelf meters are inexpensive to replace.

It's a nice looking meter. I don't have something like that yet but in terms of vintage workshop equioment, I have managed to collect three CROs, one of which, a BWD, I do use at times, and a couple of signal generators.

I don't know the model number of that meter, but it's featured on University Paton's history page:

https://www.universitypaton.com.au/page/10/our-history-university-paton

The number at bottom right of the panel (127 here) seems to be a manufacturing serial number. Is yours readable?

QUOTE: "Radio Equipment Pty Ltd" was a historical Australian electronics and radio manufacturing company based in Sydney (located at sites like Kent Street and North York Street) from the 1930s through the post-war era, famous for producing "University" brand testing instruments, multimeters, and signal tracers.

Hi John!
First thing , is the meter movement ok?
If it reads DC ranges accurately then probably yes.
If not, either the movement has a problem or a resistor value is way out.

If the AC reading is low then probably the internal rectifier has failed.
My memory tells me they used a round selenium plate rectifier.
That will have died by now.
Probably will just test like a set of resistance values backwards and forwards.

A set of modern germanium or silicon diodes may fix the problem.

Cheers, Fred.

A new Silicon Diode with a voltage like 1000V plus, depending as to where it is electrically; will be more efficient & require recalibration. EHT on my Heathkit Oscilloscope gained, and needed to have tamed an extra few hundred volts after the Selenium stick rectifier failed & was replaced with a TV diode.

The AVO 7X (have junk ones) used a transformer to get the swing & power needed to drive its meter with the AC Range. This I doubt, being of the era, is much different. The AVO went funny after a cap in it died. That is becoming common in old test equipment and old caps especially paper & oil need tossing out.

It may be a long shot that they have archived the info: I have and have repaired Paton VCT's, But fortunately have the original paperwork.

A related aside the Chaff shed here is over 100. The upper front chute door is clad with Kerosene Tin flattened out. To preserve it, it was painted, when a new frame was built. Its Embossed "Bio co limited. with a "Shell" emblem. I had always suspected that was Shell pre 1930's. Shed is log construction and was built by the same builders as the next door farm.

Seeing that Shell is celebrating 1901 to current. I sent a photo to their media contact & actually got very useful feedback. The tin is actually "British Imperial Oil Company" Registered in Wellington NZ 1912 then Shell in 1927.

It did pay to enquire.

GTC, the number is 944. I'll have a look at the Paton page too!

Brad, yes, I always leave my Jaycar meter on the1000V AC scale.
& after carefully reading the instructions(!) I always leave my Heathkit VTVM's on anything but the ohms scale. Apparently the internal battery can run down when left in any of the value positions.

Fred, yes, the movement seems fine - no sticking. I'll track down the rectifier & replace it.

& Thanx all for the help offered. I'll check out Kevin Chant's excellent site.
John.

Most of the ordinary meters perhaps have an issue left on ohms: However, never a good idea. Most of the meters that are liable chomp batteries, or run on the mains, will have an off switch.


Meters without a dedicated off switch, I consider a PIB as you cannot leave them on a range & just turn it on & off to save battery. Rather than have to manhandle the thing. Two Micronta ones I have, have dedicated on/off switches.

Some analogue meters had an off that shorted the movement as a dampener, when the device was moved around.

OK, thanks to this new post we see that the "MVA" on the panel is in fact the model:

https://vintage-radio.com.au/default.asp?f=4&th=32

And there's an MVA-2 user manual containing a schematic here:

https://www.kevinchant.com/uploads/7/1/0/8/7108231/mva_2.doc

I note MVA-2 is showing a full wave rectifier. That really has to be replace with same, if faulty. Small block ones are made. It would pay to have the one in it identified (photo) to see what it might be?

0.5μF cap (0.47uF) 472. I would tend to replace with a line cap to get the voltage rating high. If its not ceramic.

Gentlemen, thanx so much. & nice to see someone else with the same beastie, complete with the manual. I'll get to play around with mine as time dictates.
(Grateful) John