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NickG0HIK 2nd Jun 2019 3:19 pm

Model 40 Universal AVOMeter
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A friend gave me an AvoMeter Model 40 yesterday as he was having a clear out.

I might have passed over this one as I have a Model 8 that I use regularly, but I collect aircraft equipment and the A.M. mark got me interested.

It was very dirty, but after a good soak with weak mixture of water and washing up liquid and the use of a nail brush and tooth brush it started to look presentable.

On the bottom I found the inscription.

"Master AvoMeter Do Not remove from the ELec Bay, New Issue 5/5/58"

A nice bit of history.

I redid the engraving with some "KiwkFill" crayon and it is a smart addition to my collection.

It does not work, but what the heck, maybe a job for another day.


Sinewave 2nd Jun 2019 4:06 pm

Re: Model 40 Universal AVOMeter
Could well be a Model D with a Model 40 front on it.

What does the rear plate say?

NickG0HIK 2nd Jun 2019 4:23 pm

Re: Model 40 Universal AVOMeter
Yes, indeed the back says Model "D".

Is there a good web site where I can read up on the models and history ?

AndyGilham 2nd Jun 2019 5:15 pm

Re: Model 40 Universal AVOMeter
Search this forum, plenty of very useful information from the experts.
Additionally, check out


The Philpott 2nd Jun 2019 5:31 pm

Re: Model 40 Universal AVOMeter
A good looking Model D. They are quite robust, 70 or 80% chance it is capable of being made fully functional. Don't attempt to turn the Q knob, as it is glued firmly in place and has no function on this particular model- other than filling up the hole!

I'd like to see a picture of the inscription. A lot of meters of this vintage got recalled back to the factory after a decade or so of use, for refurbishment. It could be one of those.
Sometimes an ACW mark can be seen painted onto the scale plate along with the date, indicating the meter has been reconditioned.

An accurate and quite useful meter even today, provided it is barred from uses where electronics might be damaged. In my opinion it is well worth returning it to working order if this can be achieved. (Plenty of rainy days...!)


NickG0HIK 3rd Jun 2019 10:48 am

Re: Model 40 Universal AVOMeter
1 Attachment(s)
Thanks for the link Andy, that was an interesting read over my morning coffee.

I've included a photo of the bottom for you Dave.

I might get around to having a look at it Andy, there are plenty of rainy days up here in Cumbria, but I also have plenty of rainy day projects too :)


Superscope 3rd Jun 2019 1:19 pm

Re: Model 40 Universal AVOMeter
Hi Nick,

Is it's Serial Number still visible on the Scaleplate?

If so, could you report it on the "Multimeter Survey" Sticky Thread?


NickG0HIK 4th Jun 2019 9:27 am

Re: Model 40 Universal AVOMeter

I've added this and my AVO 8 to the database.


high_vacuum_house 4th Jun 2019 2:49 pm

Re: Model 40 Universal AVOMeter
I am interested in what the KWIKFILL crayons are as I have a few AVO’s that have had the white filling fall out. Looking it up just comes up with petrol stations!!
Many thanks,
Christopher Capener

NickG0HIK 4th Jun 2019 6:59 pm

Re: Model 40 Universal AVOMeter
Well it would help if I spell it correctly.

"KWIKFYL" is the correct name I think, I've have had mine that long most of the lettering on it is missing.

It is rather like a wax crayon, but is a bit more dense.

I think I got mine from an "Old Timer" when I worked in an instrument Lab, he used to work for Cambridge Instruments and told me stories about hand winding resistors and painting meter dials with "Indian" ink.

I seem to recall he just told me rub it over the dial and push it into the engraving, but this time I tried warming the dials with a hair drier. This worked really well, just softening the wax enough to fill every nook and cranny. Then clean off with a solvent such as IPA.

A quick "Google" does not come up with any useful links , but you might find a picture of what it looks like, much like a small white "Toblerone" without the pyramids.
It appears it does turn up on Ebay although none is listed presently, so keep searching.

The Philpott 4th Jun 2019 9:01 pm

Re: Model 40 Universal AVOMeter
I got sticks of engraving wax in the mail from Trading Post in Shifnall, but it is arguably slightly too bright a white for this purpose. The surplus is removable with meths. The alternative i used on subsequent jobs was Revell Enamel model maker's paint, (i used an off-white colour closer to ivory) allowed to dry for a few minutes then wiped down with a rag soaked in Revell's own thinners. You can blend the white with another colour to dull it down depending on how old the meter is.

Both of these systems are a bit of a pain to remove from the crackle finish used on Avometers, so it's best to avoid getting them in there in the first place.


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