AVO Multimeter survey
 

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Also see post #638 in the current thread:-
https://www.vintage-radio.net/forum/...&postcount=638

See also post 1530 and 1533 with regard to an on-line database being created for these meters:-
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I am trying to compile an unofficial history of the AVO multimeter (unofficial beacause there is no official :( interest in the project).

I doubt if there are many Forum members without at least one AVO, so there should be enough material for me 'out there'/'in here'.

If each of you could let me know the Model & Serial number of any AVOs in your possession, I should be able to derive quite a story from the information.

I'm sure that many of (y)our multimeters were, er, liberated ;), so in order that they and their owners remain untraceable 8) I suggest that all but the first digit of the first number group be replaced by Xs.

Thus my 8 mk2 54112-C-1256 would become a Persil-white 8 mk2 5XXXX-C-1256. (The letter and the numbers in the last group are important ).

If you post your replies in this thread everyone will be able to see how the survey is going :o. If you're bashful :-[ you can use the PM channel.

It doesn't matter which model you have - the older the better for my purposes - if it's got a serial number on the scale plate I'd like to know about it.

I'll post any conclusions so all who contributed can say " I was there on St. Crispin's Day " .

Thanking you, as they say, in anticipation.

Cheers

Re: AVO Multimeter survey
 

I will check-out the serial numbers of my AVOs when I am home from Uni (an 8 MkIV, and a 7 MkX I think). There are a few hanging about at the back of the electroncs lab at Uni, but I'm not sure if they would like me taking them off the shelf! ;D

Sam

Re: AVO Multimeter survey
 

Greetings,

Model 8 Mk 3 Ser. 77157 368

Much appreciated, mint condition, original owner - sadly not much used now except as a peak indicator for alignment. 5 Lithium batteries work brilliantly to power the high ohms range, and fit between the clips taped as a stack, fitted with a spacer.

Leon.

Re: AVO Multimeter survey
 

Hi spch
Model 8 Panclimatic 75370 C 658
Excellent condition - metal outer case finished in a sort of hammered bronze - owned for 30+ years - good condition. Originally from surplus shop in Warrington.

Re: AVO Multimeter survey
 

Hi, I have a Model 7 mk2 No 1108-A-1164
The meter is near mint and has all the original leads and probes and AVO instruction manual. I paid £10 at a boot sale about 8 years ago. :). It doesn't often get used, I tend to prefer the convenience of a modern cheap digital meter, :-[.

Regards, Mick.

Re: AVO Multimeter survey
 

I've got an 8 Mk2 but it's number is partly worn. It's defo 95151 - C - and the last digits appear to be 1159.

My other is a 7 ( no Mk ) number 28908 - A - 1151.

Re: AVO Multimeter survey
 

My workshop 8 (the other is buried in a box somewhere) is :

Avo 8 Mk.V - 2 0031914 AC

Talking of AVOs, can anyone recommend a cheap source of replacement leads & probes?

Re: AVO Multimeter survey
 

I have a Model 8, Ser. No. 105991-C-460 which I bought last year for £30. It came with a hand-written calibration certificate.

Gordon.

Re: AVO Multimeter survey
 

Hi SPCh

I have an AVO 8 Mk V. Not sure if it was liberated but I know it was going to thrown out. The serial number is 0XXXX 8V/1/74. It looks a bit different from the others in this thread. Could the last part (1/74) be its date of manufacture?

Regards,

Ken.

Re: AVO Multimeter survey
 

Yes, Ken. I suspect the old numbering scheme stopped in the 60s, when soulless mass production set in. The early models had personality, with someone who cared cossetting them through final test & calibration.

Keep 'em coming guys & gals. Use XXX anyway. That way you unpoint your fingers for those ...

Steve

Re: AVO Multimeter survey
 

Hi SPCh,

I actually never owned an AVO. However, I have just seen one in a secondhand shop lost among some old furniture, clothing, paintings, etc. I was considering buying it. It is missing its battery lid, but other than that looks OK.

I was going to ask for opinions should I buy it. If I do buy it, I am tempted, then I will post the serial number and details for you. However, I do not know whether you are interested in AVOs from Australia in the first place. ???

Regards
Andrew

Re: AVO Multimeter survey
 

My Model 8, - 136361-C-362
purchased from Telecom (Aust) auction for $50 some years back and then scrounged all the accessories, instruction book & 10 KV DC Multiplier and lead through work

Harv

Re: AVO Multimeter survey
 

The resident Model 8 is 59054-C-457.

There's also a Thorn period Model 7, 88000 7/11/75.

Paul

Re: AVO Multimeter survey
 

Avometers Serial Numbers As I believe them to be:

This is based on much research and a little speculation but appears to conform well to the other known facts - examples are taken from actual instruments. Model numbers in brackets were not used by Avo or the The Automatic Coil Winder and Electrical Equipment Company (ACWEECO) as they were before about 1953. If you can add to or correct to this list, please let me know.

'The Avometer' (Model 1) 1923 -1927 six figures, e.g. 135923

DC Avometer, 13 range (Model 2) 1927 - 1936 four figures e.g. 1562, 3588

Universal Avometer, 20 range 1932 - 1933 (Model 3)
M(M)Y XXX, where M is the month and Y the year within the decade. e.g. 13-919 January 1933, ser. no. 919

Universal Avometer, 34 range Dec. 1933 to June 1934 (Model 4) - As for 20 range Universal (speculative no example available).

Universal Avometer, 36 range (Model 5) 1934 - 1939
As for 20 range Universal

Later DC Avometer, 22 range (Model 6) c 1935 to 1939
Unknown, believed to be as for 13 range DC Avometer.

Early Model 7 Aug 1936 to 1947
7M(M)Y XXXX e.g. 729-2613, February 1939, ser. no. 2613

Early Air Minstry Spec 'D' 10A/10610 as for 20 range,
e.g. 39-8232, March 1939, ser. no. 8232

Model 40, original type, 1939 XXXX M(M)YY e.g. 2438-640
Serial no. 2438, June 1940

Later, early Model 40, as for Model 7, e.g. 404941-543, ser. no. 4941, May 1943

Admiralty Pattern 47A, 48A, XXXX-M(M)YY
e.g. 9299-842R ser. no. 9299, August 1942 - suffix possibly variant or production plant?


Later Air Ministry Spec. 'D' 10S/10610,
DXXXX-M(M)YY, e.g. D1631-241, ser. no. 1631, Feb. 1941

All models from c. 1947 to 1973, XXXXX-V-M(M)YY,
e.g. 656-B-248, Model 40, serial no. 656, variant B, Feb. 1948 (Variant B of the Model 40 does not have reverse AC overload protection diode across movement and has modified swamp coil).
Air Ministry Model 'E' is an exception, e.g. E349 1954
Serial no. 349, made 1954.

After 1973 to date
Serial No./Type/M(M)YY, e.g. 92936 8V/7/73

Model 8 Mark V, serial no. 92936 July 1973
with variants which even Avo can't explain.

As you will gather, I don't have a 34 range Universal or a 22 range DC Avometer, but I am interested in acquiring them.

Re: AVO Multimeter survey
 

My Contribution:
Universal AVO minor 68160-744
Avo Minor 6xxxx-742
Heavy Duty AVO 7xxx-957A
AVO7 7xxx-26082
AVO8 2xxxx-C-1154

Re: AVO Multimeter survey
 

Hi SPCh

2 AVOs here,

AVO 8 Mk V, serial no. 96246 8V/2/76

and a spare, stuck in the shed.

AVO 8 Mk III, serial no. 144882.C.862

Richard

Re: AVO Multimeter survey
 

Here's mine: AVO Model 8 Mk IV, serial number 5XXXX 84-9-71

Re: AVO Multimeter survey
 

I've just unearthed an AVO Multiminor MK 4 ,
No 68829 Date (written inside) 29-4-69 ?

Is there any truth in the rumour that the government is thinking of imposing a possession tax on Avometers? Apparently they are already collecting serial numbers... :o.

Regards, Mick.

Re: AVO Multimeter survey
 

3 Avo's out here in Mexico

Model 8 Mk.II (with bad shunt) #132275-C-1261
Model 8 #2715-C-152
Model 7 #29062-C-1151

Personally, I find a cheap DMM to be faster but the AVO's (and all the Marconi VTVM's I have) have their uses.

Adrian

Re: AVO Multimeter survey
 

Hi SPCh,

I went to check out that AVO properly and then wanted to offer to buy it. Well, the lady was frantic when I lifted it off the shelf. She said you either buy it or do not touch. I poited out to her that I was interested to buy it and I wanted to check to see if all was OK as a few things were missing, like the battery compartment lid and the clip for the black lead. I also saw one of the knobs melted probably from a soldering iron. She responded that people steel things, that is why those things are missing. Then she took it from me and put it up on the to shelf behind her. She said this is antique and whether it works or not it will cost you $85.00. I thanked her politely and walked out.

If I saw it correctly it was an ex Telstra unit from Sydney and appeared to be model 9x if there is such a thing. I saw the serial number too, but I did not have a chance to take it down.

Well I just have to continue using my dust collecting 99 other test meters. I suppose the really good news is that now I can spend this money on something else I really do not need.;D

Regards
Andrew

Re: AVO Multimeter survey
 

Hi all.
Just come in from the workshop. Mine is an AVO 8 Mk 2
Sn 9568 C 12 575.
The numbers have been hand painted over the original printed serial number.
I think this may be an ex military one, which I picked up at a radio rally ten years ago.

Re: AVO Multimeter survey
 

Hi

I've an 8 MkIII no. 45501 866 complete with leather case & leads that was crying out for a new home. Its old home went out of business years ago.

Also an 8 Mk5 No5270 045 that cost a fiver at a radio rally having suffered smoke damage - internally! Its reasonably sorted now apart from one voltage range.

And also an Avominor No 94484-1252 that came from a neighbours dustbin, together with many other treasures over a long period, but thats another story, well off topic!

Joe

Re: AVO Multimeter survey
 

I've got an 8 Mk III - number 7126.1264. Am I looking at the wrong number - or is this an odd one?

Jim

Re: AVO Multimeter survey
 

Few more for the list:

Avo Minor 60219-140
Avo Model 40 17845-247
Avo Model 7[Mk I] 7647-35840
Avo Model 7 Mk II 54149.A.355
Avo 8 Mk.II 129803-C-1061

Re: AVO Multimeter survey
 

Ah, I was wondering where that had gone, and there it is on the cassette shelf:

Avominor: 64391-641.

Paul

Re: AVO Multimeter survey
 

I have an Avometer NATO Stock Number 6625-99-650-2823. On the back it says it's a Model 8 Mk V. The only sticker which looks like a serial number says " 0029979 LB 8V " .

Re: AVO Multimeter survey
 

Hi all

My two AVO 8s as follows:

127198-C-961
73303-C-458

I can't find any mention of Mk. number so are presumably Mk Is. Where is the Mk Number normally put?

Cheers
Brian

Re: AVO Multimeter survey
 

Brian,

From the serial numbers, your Model 8s were made in September 1961 and April 1958. That makes both Mark IIs.

The main difference between these and the Mark I is that the movement magnets are Alnico in the Mark I and Alcomax in the Mark II. The Alcomax magnet is crackle red painted and is shorter than the Alnico magnet. Externally, the Mark II has red and black socket terminals rather than the knurled black terminals of earlier meters.

You will probably find that the 1958 meter has an unused gap on the selector switch between the 250V and 1000V (DC) ranges. On the later meter there will be a 500V range.

Avometer Mark and Model mumbers are neither entirely logical or consistent. This could perhaps (this is speculative) be because, in the 1950s and 60s the company was run with some degre of autonomy, I have heard it described as autocracy, by Hugh S. MacAdie, son of the original patentee, Donald MacAdie.

For example, there never was, as far as I know, a Mark I or Mark 3 Model 9. The first Model 9 was produced in parallel with the later Model 8 Mark II and was called the Model 9 Mark II. The Model 9, Mark IV was very similar to the Model 8 Mark IV.

Avometer 'Marks' on came into use in the late 1950s; model numbers were not used until 1936, and then somewhat uncertainly. The early Model 7 (from August 1936) was often advertised as the " 46 Range Universal Avometer " with Model 7 almost as an afterthought.

When the Model 7 got socket terminals it became the Mark II. Otherwise there was little change. Earlier however, a more significant redesign which replaced the original movement which had a horseshoe, nickel-iron magnet with the more modern alnico block type (c1947) went unmarked in catalaogues or advertisements.

The Model 7 Mark II slowly evolved internally to use fewer wound wire resistors and more component resistors throughout its production up to the 1980s. None of the changes were thought sufficient to call for a change of mark. The huge block paper 1 microfarad capacitor which lived alongside the scaleplate of the early Model 7 became an, almost dissapointingly small, film dialectric capacitor in the final versions.

The addition of a fuse, a thermistor and a different grade of alcomax magnet were enough to distinguish the Model 8 Mark III from the Mark II (1964).

Re: AVO Multimeter survey
 

Thanks for the info on my AVO 8s.

I have also found a Model 7 MkII S/N 33945 7/271

Cheers

brian

Re: AVO Multimeter survey
 

Hi SPCh. I am home from Uni, so here are my Serial Numbers:

Model 7 (Says 'MODEL 7X' on the front): 64424.A.556. This is on the scale-plate, and the 1, 1.5, and 2 on the Power scale have been added in red by hand, in the same style as the serial number. I guess this could have been a military one, as there is another number on the case (on the front, at the top) which is: ZD 02995, followed by the little arrow. The unit appears to have been serviced at some point by LIRC. On the working instructions on the back it says 'AVO Ltd, a member of the Thorn Group'. Plenty of info there! ;)

Model 8: I can't see a Serial Number on this. ??? Where are they! All that is on the scale-plate is '8 IV'

If you want them, I can try and find the Serial Numbers for tha AVO Bridge and Signal-Generator I have too.

Sam

Re: AVO Multimeter survey
 

Hi SPCH

I have got a Model 40 Universal but on the back it says Admiralty pattern 47A.

Sorry no serial number.

Maurice

Re: AVO Multimeter survey
 

Hi SPCH,

A model 8, Mark 3. Serial number 14445.465 - Imagine my avo was an SA export one? I have replaced the high ohms range battery with some lithiums. Think I paid aprox 15 pounds.

Andrew

Re: AVO Multimeter survey
 

I have a Universal Avometer Model 8, Ser. No. 80691-C1058, which I got from colleagues when retired.
I have been using AVOs from mid 1960es till early 80es. Great instruments!

Ake
Finland

Re: AVO Multimeter survey
 

Yes they are, Ake. I've been using them since the late 1940s, and my father before me from the early 30s. And the old ones are still going strong (like me, I suppose) ;)

The original batteries are long obsolete, replacement test leads now cost more than the meters themselves, but they're still infinitely better than the oriental digital flimsies which somehow can't quite displace them !

Which is why I collect them and, if not them, their serial numbers.

Thanks to everyone who's replied so far; keep them coming, though. As I've heard of nothing pre-1935 I have to conclude we're a classy, progressive, sensitivity-demanding lot.

Re: AVO Multimeter survey
 

My contribution.
AVO Multiminor serial number 016554
gift from my father when I passed my intermediate C&G in Radio/TV servicing.
repaired once and still in use.
dave Leicester

Re: AVO Multimeter survey
 

Hello from Ontario Canada. May I give you some details of my AVO meter. I found it in my fathers basement after he died last year so I dont care if he stole it, they can chase all over Hell after him if they want.

On the back it says Instructions for use of AM test meter Type D Ref: no.10S/10610. At the bottom it specifies cell No. 6 REF. no. 5S/2000 and gives patent numbers 200,977 and 404,015.

Cell is missing and so is the cell compartment cover. The gauge has also been removed. So its really a hunk of junk, but an interesting hunk of junk, the heaviest VOM Ive got and the only one with a bakelite case.

Can anyone tell me how old this thing is.

Re: AVO Multimeter survey
 

Your AM Type D Avometer is of Second World War vintage. This version was in production from about 1939 until 1947. (There was a previous variant made from 1938, I've only ever seen the one I have so I can't give a more exact date).

They were widely offered for sale on the surplus market in the 1950s and still appear from time to time on ebay. They are one of the most common types of Avometer of their period which appear on ebay.

From the ranges chosen, I believe that this meter was specified for use on aircraft and motor vehicle electrical systems but I would very much like to have confirmation from someone who either used it officially for this purpose or who has documentary evidence.

If anyone is intersted, I can post a detailed description of the Model D.

Re: AVO Multimeter survey
 

I have:

Model 8 MkII 105043-C-360
Test set No 1 12195-8-71 (ex RAF last calibrated 1989)
Model 7 6412-A-748

Last two purchased for £2 each last year! The movement of the model 7 only indicates correctly when the instrument is horizontal.

Re: AVO Multimeter survey
 

Hi,

My contribution: AVO Model M808 digital Serial No. 51404718
Bought new about 6 years ago and in daily use.

Tony.

Re: AVO Multimeter survey
 

My AVO 8, which had a faulty movement, was given to me when I was an apprentice and so I got a good meter for the cost of a professional repair. I think the repair was about £12, which was a significant sum in the 1960s.

The serial number is 82573-C-1158 and I think it is a MKII although there are no markings to indicate MK number. When would it have been made?

Re: AVO Multimeter survey
 

Colin,

As you'll see on the first page of the thread, your meter was made in November 1958, so it wasn't very old when you got it. The £12 repair was about half the new cost in the 1960s.

Re: AVO Multimeter survey
 

From the Left coast of the Atlantic -
Model 9SX, Pan-Climatic No. 1, S/N 1210-1S-461, Lower left corner. Brown Bakelite Panel, Bronze paint metal case, green vinyl carry case.
NATO, No. 1, S/N 5150, Lower left corner. Brown Bakelite Panel, Bronze paint metal case, green vinyl carry case.
Model 40, S/N 8433-B-1152, Lower right corner, Black bakelite, 166-ohm/volt DC sensitivity. Fitted wood case with shunts, current transformer, and voltage extender.
Model 8, Mk II, S/N 148617-C-1162. Black Bakelite.
Model 8 Mk V, S/N 51985 8V/1/75. Black plastic. S/N in battery compartment.
Model 8 Mk 7, S/N ??. Black Plastic.
Model 8 Mk ??, 18913-C-1253, Lower right. Black Bakelite Panel, Gray metal case, terminals do not accept banana plugs.
Model 8 Mk 6, S/N 1063BE Decal on rear. Black plastic.
Model 7 Mk II, S/N 84528-A-460, Lower right. Black bakelite panel Gray metal case. 500-ohm/volt DC sensitivity. Made by Automatic Coil Winder.
Is that enuf for now?

Re: AVO Multimeter survey
 

In our test department at work there is a model 7 gathering dust. Serial number 01612 7/3/77

I'm not 100% sure about the last 7 as it is partially rubbed off.

Re: AVO Multimeter survey
 

Hi SPCh. I'm a newbie to this forum, I came accross it while googling for info on a Model 7 Avometer that has just been given to me. It has this serial number on the bottom RH side of the scale 7XXXX-A-557. It has a black Bakelite face & battery cover, a hammertone gold painted body & a gold instruction plate screwed to the back which also bears the model & patent numbers. It also has the 1, 1.5, 2 & the W hand printed in red on the power scale. It seems in very good condition & the only deviations from standard are the probes & a modified battery compartment - A "C" cell & holder plus a 9volt battery connector soldered onto the appropriate tabs that would have serviced the 2 x 4.5 volt batteries. Also, it has a decal on it stating it was sold by the Australian agent Electrical Equipment of Australia Ltd. 75 Liverpool St, Sydney.

Hope this helps your survey.

Re: AVO Multimeter survey
 

Hi

I've had about 8 in the last 2 years, including a AM one from the WW2 period.

Currently I have a lovely model 7 in excellent condition which nobody wants ...it's number is 21669-A-251

Cheers


Tony.

Re: AVO Multimeter survey
 

An AM Avo meter?????? now I'm really puzzled.

Mike

Re: AVO Multimeter survey
 

I think "Air Ministry", Mike, not "Amplitude Modulation".

Sorry guys and gals; I've been out of circulation for a few weeks. Thanks for the new inputs, they'll be absorbed & processed over the next few days, and I'll get back to you individually for any queries/clarifications.

Re: AVO Multimeter survey
 

Thanks SPCh it seems the older I get the dafter I become.

Mike.

Re: AVO Multimeter survey
 

I have an AVO 8 MkIII.

Serial number; 89672 1268

This would indicate a production date of December 1968.

As I now know; the MkIII was introduced in 1964 and the MkIV in 1968, so my MkIII must have been a very late one.

Re: AVO Multimeter survey
 

Avo 8 MkV bought on ebay last year :-), so serial number is: 0xxxx 8V/4/77. Told it was a college sale. Great meter, great condition, great buy.

When I was apprenticed to EKCO in Glasgow I bought a wee Avominor. A while later it got nicked :'( >((. Wish I could remember the serial number!

HTH
Jim