AVO Multimeter survey

[Phil G4SPZ]

Originally Posted by sparkymike

...might be just a case of corroded wander plug sockets... my father... was involved in switchboard plugs for BT...

I’m sure your father would recall Greygate ‘Paste Polishing No 5’, which was specified by the GPO for polishing the tarnish off the brass plugs. It also works wonders when applied sparingly on a cotton bud and rotated down the wander plug sockets of AvoMinors!

[sparkymike]

I have started the list of my AVO meters.
I will post photos in order in my albums.

(1) AVO test set multirange no.1
Serial no. 313.1266

(2) AVO model 8
No. 87895 1168

(3) AVO model 8
No. 105201 1069

(4) AVO model 7
No. 28279-A-1051

(5) AVO model 8 Mk.3
No. 32817-1265

(6) AVO model 8 Mk.2
No. 113838-C-1060

(7) AVO model 7
No. 7104523535
Note: In wooden case stenciled on front, "TYPE P4A"

Mike.

[sparkymike]

The first four meters are now in my album.
Mike.

[The Philpott]

..The wander plug sockets can generally be cleaned up as Phil says, sometimes i have resorted to 600 wet & dry wound into a cylinder shape where they are very grotty. The split pins have a small contact area of course, such that a little patch of (a real pain to shift) verdigris or dezincification can upset the readings.. some avominors have 'twizzle' marks on the bakelite where people have spun the terminals round in frustration.

Dave

[sparkymike]

Hi Dave,
Thanks to your advice, the Minor is now working on all ranges. I managed to
squeeze a 2K resistor under that shunt coil and bridge the offending coil.

Mike.

[The Philpott]

Good- but wasn't it the 8kohm one that was o/c..? (25v) ?

5v-2k
25v- 8k +2k (ie 10k)
100v- 30k + 8k + 2k (ie 40k)
250v- 60k + 30k + 8k + 2k (ie 100k)
500v- (50k+50k) + 60k + 30k + 8k + 2k (ie 200K)

As you will have seen, 2 extra bobbins are used for 500v range.

Dave

[The Philpott]

Here's one i dismantled earlier...!
The bobbin with the pink triangle on it should be 8kohm, that will enable the 25v range to be accurate (if all other aspects of the meter are ok)
If you have given it 2k the 25v range will now be a 10v range!

I use 330k and 8.2k in parallel to get 8k, as those are the values that i have plenty of.

Dave

[Sinewave]

I've got in front of me what appears to look like a model 8 mark 1. However it has the steel casing for the rear which is grey. It says on the back that it is a model 8, but doesn't mention whether it's a panclimatic model.

At the top of the meter it has markings 10S/16411 with the nato arrow. It's in a leather case marked 10S/110 with the nato arrow.

Quite an interesting looking version which at first glance looks like maybe an 8X mark 1.

[avocollector]

Latest acquisition
Avo 8 mk V
Serial No sticker on side 05466 8V/11/79

The meter movement itself has some broken plastic components (not seen them yet) so it may eventually be a donor.

[Aitor Eneko]

Hello my name is Aitor Eneko, i live in Canary Islands, Spain, excuse for my English.

I am 48 years old and i used Avo meter since 1988 when i began repairing valve radios and others. Now, i repair mobile phones and others, i do micro soldering, and i sometimes use an AVO 9 mk4 that i owned for 25 years.

A few months ago i decided to begin my AVO collection. They are difficult to find in Canary Islands, but i do not have problem to buy them abroad.

Here you are my serial numbers:

AVO 9 mk4 no serial number on dial, case or interior. Just AVO 9 on dial
AVO 8 mk3 serial number 42448-666
AVO 7 MK2 44799-A-1053

I hope to learn here and to help too.

Aitor Eneko

[The Philpott]

Thankyou for your serial numbers, Aitor. You English is much better than my Spanish, i only recall 'Una cerveza por favor' from my lessons..

I too am age 48, the Avo 8 Mk3 and Avo 7 will probably still be working when we are old and grey (but perhaps the Avo 9 Mk4 may not be!)

Dave

[Aitor Eneko]

i only recall 'Una cerveza por favor'

That is enough to survive in Spain, so congratulations!!!!

[Superscope]

Welcome to the Forum Aitor,
Thank you for your Serial Numbers.

Can I confirm that your Model 7 is definitely a Mk II ?

1953/1954 is a bit of a Grey Area for the Serial Number Database.
In the early days of this Thread, the Mk version wasn't always given.

I had assumed 1954 was the transition from Mk I to Mk II for the Model 8 and I thought the Model 7 and 40 would be the same, but I am guessing now that the Model 7 is actually 1953.


Dave,
Talking of Mk's, could you tell me the Mk's for your AvoMinors you posted on Google Docs for the record?
I've never got my Head around AvoMinors, so the Dates don't help me much. :-(

The Database currently has 1630 Entries recorded.
I hope to get the next List out shortly.

Ian

[Sinewave]

Originally Posted by Superscope

Welcome to the Forum Aitor,
Thank you for your Seriel Numbers.

Can I confirm that your Model 7 is definately a Mk II ?

Quite likely is. I have a 7 Mk2 from 1952 - full working order too.

It's the era where there was a mk1 and mk2 cross over, where the mk2 came in with the power factor terminals at the top, yet the - and + terminals at the bottom were still the old mk1 style terminals.

[Superscope]

Hi Sinewave,

Does your 1952 Model 7 actually have the Mk II ID on the Front ?

Looking through the records, I have also found a few references for Mk I's well past 1953,
so I guess there was quite a cross-over.
Although, I can only go by what was reported, so Typos or Hybrid Meters might also be involved.

Incidentally, do you have your Serials for your Military Stash to go with the NSN's we spoke about previously?

You never know, one day we might get to the bottom of AVO serial Numbers, but not any time soon.

Ian

[Aitor Eneko]

Originally Posted by Superscope

Welcome to the Forum Aitor,
Thank you for your Seriel Numbers.

Can I confirm that your Model 7 is definately a Mk II ?

1953/1954 is a bit of a Grey Area for the Seriel Number Database.
In the early days of this Thread, the Mk version wasn't always given.

I had assumed 1954 was the transision from Mk I to Mk II for the Model 8 and I thought the Model 7 and 40 would be the same, but I am guessing now that the Model 7 is actually 1953.

Ian

Here you are the photos, pephaps is a transition model. The movement is damaged and the blue resistor is not original.

[Superscope]

Thanks Aitor,

Always good to have a Photo.

I would say this is simply a Late Mk I
Due to the older Style Terminals and the fact that the Ident Label only says Model 7 (not Mk II).

Although the Mk Numbers were a bit academic regarding the Model 7 and 40, as there were only
Two official Mk's, but as we all know, there were many changes along the way at different times, mostly hidden inside.

Regarding the PF connectors, I think somebody on here mentioned previously, that these were an option when they were
first introduced, so Mk I's and possibly Mk II's as well, may or may not have them.


Ian

[Aitor Eneko]

Then it s a MKI second model.

I thought that these Mk I second model were made between 1944 and 1951 and mine is october 1953

[Sinewave]

We're getting some kit calibrated at work. I mentioned about whether I can add one or two of my Flukes into that.

My boss said "that should be fine, but don't bring along 8 million Avos for calibration" (he's aware of my Avo collection, though 8 million is stretching it)

[sparkymike]

Details and photos of my AVO 8 Mk.5.
It is the cleanest one I have seen so far and looks like it has hardly been used if at all.
Serial No. GC No.0043772 8V
What year would this be? 72 ?
Mike.