AVO Multimeter survey

[Superscope]

Hi Andy,
That's great to know, I will remove the duplicate record and keep the Braille reference obviously. Next issue of course!
If anybody else owns a Braille Meter, it would be great if they could update me, so I can add the information to the Survey.

This is a prime example of how important details were missed in the early days, because they were not specifically asked for.
Although to be fair, the original purpose of the Survey was primarily to ascertain production numbers.

I was surprised nobody picked me up on the Four identical Serial Numbers recorded for the Model 47A S Variant!
Ok, that's One Easter Egg out of the Bag, there are at least two more, one quite important that nobody has picked up on yet!


Ian

I think this is an error

[Superscope]

Thanks Aitor, I didn't spot that one.

Trust me, there is a far bigger one than that!


Ian

another one

[Superscope]

Ok, the duplicate Model 8 Mk I has been removed.
Reported Twice on Aug 2014 & Jun 2015.

Model 9 Mk II now also removed.
Reported twice on July 2014 & Jun 2015.

Amazingly all the above by the same Forum Member!



Ian

Today the postman gave to me an Avo 8s (mk1) no panclimatic

Serial 27306-C-854

Tag and label air minister

[Sinewave]

Air Ministry Model D's to add to the survey.

Four units

• 14806-644
• 10534-843
• 13708-344
• 8250-243

[Sinewave]

If I haven't added previously to the survey any Model D meters, there are another four in my collection, totalling eight Model D's. I'll get the numbers over later.

[Phil G4SPZ]

I thought that, in the dim and distant past, I had reported the serial numbers of my Model Ds, but if not, here they are, all two-and-a-half of them...

"D.46-1048. R1949" This instrument has the Air Ministry 'A-crown-M' logo at the top centre of the scale plate. I take this to be an October 1948 instrument, repaired in 1949. Working but unrestored.

"342-D-9/1951" This instrument is also engraved with '10S/10610' and the Pheon ('Broad Arrow') symbol on the front panel above the scale window. The Air Ministry 'A-crown-M' logo appears at the far left of the scale plate. Restored by me and working perfectly, complete with replica 1.5V battery.

"D.2104-541" This is a real odd-ball. It was kindly given to me by Paul Adams. It appears to be a Model D, but is built on a Model 7 front panel and has a 1mA movement. It has the "K=1/K=2" switch of a Model D, but the movement FSD is all wrong, and the last time I looked at it and tried to fathom out its workings, I gave up in despair. One for a rainy day/week/month, I think.

Phil

[Sinewave]

I just tried my AM Model D 14806-644 - working absolutely fine on volts and current DC. I've only tried the lower end up to 15mA and 15V.

It comes with an unusual battery which some of you may have seen before. It reads 1.4v too, but probably not much actual power left in it.

Interesting, so am I right to assume that this meter was still in the hands of the MOD in the 60s/70s and still in use in their workshops?

[The Philpott]

It's notoriously difficult to find out when the MOD ceased using a given technology, especially regards miscellaneous items of gear.

Phil, your D.2104-541 is interesting- a 1mA mvmnt. matches neither a Model D or Model 7 spec.. Yet if it were a friday afternoon reject it would be amazing if it had survived.
I have an odd Avominor Model 1 (1500v) that was fitted with a couple of incorrect bobbins, which survived a (probably deliberate) bash on the front which took out a chunk of the facia, but i find it much more difficult to theorise on the story behind the meter that you have.

Dave

[Phil G4SPZ]

Yes, it certainly is a strange one, Dave. 1mA FSD is correct for the movement of a Model 7, though.

The Type D was built around the 3mA movement used in the Model 40. My assumption was that in 1941 Avo might have been having trouble keeping up with orders from the Air Ministry for Type Ds, and if they were running short of Model 40 movements and panels they might have tried using Model 7 movements and panels instead. It definitely has the Type D scale plate and 0-15 scale ranges.

It certainly looks a bit like a hand-engraved one-off. See pic. I must spend a bit more time on it and suss it out.

Phil

[Superscope]

Sinewave,

Great to see all your Model D's standing to attention there, during the Roll Call

Can I confirm that all those Serial Numbers start with a D. ?
or a D- ?

I think all Model D's have a D somewhere in their Serial Number.
Maybe somebody could confirm this?

Can I also confirm (assuming they haven't been rubbed out) that they all have
10S/10610 engraved on the top of the Panel?

I don't have a Model D myself, but as I understand it, the 10S/10610 is the later
D spec meter based on the Model 40, but there is an earlier D spec (10A/10610)
based on the 36 Range.



Phil,

I'm assuming your 342-D-9/1951 has a build date of Sep 1951 ?

I have seen the full Year (Four Digits) shown in Model D serials several times in the survey,
but I was never sure if this really was part of the Serial Number or added by the Owner for information?

Your D.2104-541 has been previously reported as D.2104-541.1941
Is the 1941 actually part of the Serial Number, or was this added for info only?


Thanks in advance for the clarification Guys.

The Model D's will be included in the next Survey Report.
We currently have 36 Model D's in the Database at the moment.



Ian

[Phil G4SPZ]

Hi Ian,

Well, I have three Ds and only one is engraved on the front panel. The others have the 10S number on their scaleplates.

No, the “1941” is detached from the serial number, see image.

Phil

[Superscope]

Hi Phil,

Thanks for that update.

So the 10S/10610 is like the infamous Serial Numbers themselves?
Some appearing on the ScalePlate, and some on the outside.
Might be useful to log the location going forward.

Regarding the Year, I think if it is shown along side the Serial as per
your Photo, we should record it as such.
I'll add some spaces to show it is separate but associated, if that makes sense.


Ian

[The Philpott]

D's and E's tend to have the year shown on scale-plate in full 4 digit form in my experience.

The finger wear on the front of Phil's early D indicates heavy use- so not a reject then..
Any sign of bi-metal strip compensation as per a '7'? It could be considered an upgrade if so!

Dave

[Superscope]

Dave,

Just the Person!

I have a question about some of your Model D's.

You reported the following Serials of your Model D's a while back.

14551-544
17782-145
5422-642
18272-245

and said that they were the Early ones with the Military Number 10A/10610.
Can you confirm they are definitely 10A's and not 10S's?
The Dates and Format don't look right for the very early meters which I thought were based on the 36 Range.

Also, do these have a D in the Serial somewhere?


Ian

[micheal]

Model 7 AVOs have a 1m/a movement shunted to 2m/a. 1m/a in divde by two mode.

Mike

[Sinewave]

Originally Posted by Superscope

Sinewave,

Great to see all your Model D's standing to attention there, during the Roll Call

Can I confirm that all those Serial Numbers start with a D. ?
or a D- ?

I think all Model D's have a D somewhere in their Serial Number.
Maybe somebody could confirm this?

Can I also confirm (assuming they haven't been rubbed out) that they all have
10S/10610 engraved on the top of the Panel?

I don't have a Model D myself, but as I understand it, the 10S/10610 is the later
D spec meter based on the Model 40, but there is an earlier D spec (10A/10610)
based on the 36 Range.

Hi Ian,

Ammended list below detailing all eight Model D units.

No. D 15169-744 Air Ministry Type D. REF: No. 10S/10610
No. D 11220-1043 Air Ministry Type D. REF: No. 10S/10610
No. D 18367-245 Air Ministry Type D. REF: No. 10S/10610
No. D 8250-243 Air Ministry Type D. REF: No. 10S/10610
No. D 19627-445 Air Ministry Type D. REF: No. 10S/10610
No. D 13708-344 Air Ministry Type D. REF: No. 10S/10610
No. D 10534-843 Air Ministry Type D. REF: No. 10S/10610
No. D 14806-644 Air Ministry Type D. REF: No. 10S/10610


The writing 'Air Ministry Type D. REF: No. 10S/10610' is written on the rear panel. None have engravings at the front above the movement scale.

All units have the Air Ministry crown on the movement scale plate apart from Unit 11220-1043 which has the NATO arrow instead.

[The Philpott]

Hi Ian, i can confirm all the four Model D's of mine you mention have a 'D' Prefix on the scale plate. It's printed on, then the s/n has been painted in afterwards.

I can confirm they are all 10S/10610 meters (well that's what the instruction plates say!)

On D-5422-642, the year 1942 is NOT painted in after the serial number and date code. This meter is also different from the others in that is has the Arrow/Phaeon, not the Air Ministry/Crown logo. The feeling i got from the 1942 meter is that the scale plate and movement were replacements fitted in the early fifties. (unconfirmed) It was a real mess when i got it, with the ally back-box rotted through, but behaves the best out of them all. Sometimes the way..

Dave