AVO Multimeter survey - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Tim · 1st Dec 2004, 1:19 am

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.

joe · 1st Dec 2004, 11:15 am

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

1st Dec 2004, 6:07 pm

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

Jim

1st Dec 2004, 10:51 pm

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

Paul_RK · 12th Dec 2004, 10:20 am

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

Avominor: 64391-641.

Paul

Paul Stenning · 13th Dec 2004, 12:04 am

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 " .

brianc · 15th Dec 2004, 6:28 pm

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

pmmunro · 16th Dec 2004, 12:12 am

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).

brianc · 16th Dec 2004, 1:31 pm

Thanks for the info on my AVO 8s.

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

Cheers

brian

Sam · 21st Dec 2004, 5:50 pm

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

bizmark98 · 21st Dec 2004, 9:47 pm

Hi SPCH

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

Sorry no serial number.

Maurice

McIntyre · 22nd Dec 2004, 11:01 am

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

vahakuja · 22nd Dec 2004, 5:40 pm

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

SPCh · 22nd Dec 2004, 5:55 pm

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.

23rd Dec 2004, 12:29 am

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

Ganaraska · 18th Feb 2005, 1:51 pm

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.

pmmunro · 18th Feb 2005, 2:03 pm

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.

Barnmead · 9th Mar 2005, 4:09 pm

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.

rigsby27 · 9th Mar 2005, 6:14 pm

Hi,

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

Tony.

ukcol · 9th Mar 2005, 6:56 pm

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?

1st Dec 2004, 1:19 am	#21
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,274	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. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

1st Dec 2004, 11:15 am	#22
joe Rest in Peace Join Date: Apr 2003 Location: Edgware, North London. Posts: 307	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

1st Dec 2004, 6:07 pm	#23
Bluebottle Guest Posts: n/a	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

1st Dec 2004, 10:51 pm	#24
coherers Guest Posts: n/a	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

12th Dec 2004, 10:20 am	#25
Paul_RK Dekatron Join Date: Nov 2003 Location: Fakenham, Norfolk, UK. Posts: 4,119	Re: AVO Multimeter survey Ah, I was wondering where that had gone, and there it is on the cassette shelf: Avominor: 64391-641. Paul

13th Dec 2004, 12:04 am	#26
Paul Stenning Administrator Join Date: Dec 2002 Location: Cardiff Posts: 8,964	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 " . __________________ Paul Stenning Forum Admin/Owner and BVWS Webmaster

15th Dec 2004, 6:28 pm	#27
brianc Rest in Peace Join Date: Jun 2004 Location: Burghfield, Reading, Berkshire, UK, Posts: 1,055	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

16th Dec 2004, 12:12 am	#28
pmmunro Octode Join Date: Jul 2004 Location: Dundee, UK. Posts: 1,768	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).

16th Dec 2004, 1:31 pm	#29
brianc Rest in Peace Join Date: Jun 2004 Location: Burghfield, Reading, Berkshire, UK, Posts: 1,055	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

21st Dec 2004, 5:50 pm	#30
Sam Hexode Join Date: Apr 2003 Location: Higham-on-the-Hill, Leicestershire, UK. Posts: 338	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 __________________ Can he lead a Normal life, Doctor? No, he will be ... an Engineer.

21st Dec 2004, 9:47 pm	#31
bizmark98 Retired Dormant Member Join Date: Dec 2002 Location: Wigmore, Kent, UK. Posts: 102	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

22nd Dec 2004, 11:01 am	#32
McIntyre Retired Dormant Member Join Date: Sep 2004 Posts: 0	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

22nd Dec 2004, 5:40 pm	#33
vahakuja Triode Join Date: Feb 2004 Location: Halikko, Finland Posts: 25	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

22nd Dec 2004, 5:55 pm	#34
SPCh Rest in Peace Join Date: Nov 2004 Location: Antwerp, Belgium Posts: 345	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.

23rd Dec 2004, 12:29 am	#35
daveg8szx Guest Posts: n/a	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

18th Feb 2005, 1:51 pm	#36
Ganaraska Retired Dormant Member Join Date: Feb 2005 Posts: 1	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.

18th Feb 2005, 2:03 pm	#37
pmmunro Octode Join Date: Jul 2004 Location: Dundee, UK. Posts: 1,768	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.

9th Mar 2005, 4:09 pm	#38
Barnmead Pentode Join Date: Dec 2002 Location: Norfolk, UK. Posts: 168	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. __________________ Richard

9th Mar 2005, 6:14 pm	#39
rigsby27 Retired Dormant Member Join Date: Sep 2003 Location: Wolverhampton, West Midlands, UK. Posts: 64	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.

9th Mar 2005, 6:56 pm	#40
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	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?