AVO Multimeter survey

[pmmunro]

Ian,

Thanks very much for the detailed information on the early Model 7 and especially for the photographs.

You've answered a question I've been thinking about for many years concerning the range switches. I had come to the conclusion that the "modern" style of switch, with face cams, must have been introduced with the first of the Model 7s, but you're meter shows that this is not the case. Now the question becomes, when were the newer style switches first used? As far as I know, the newer type were also used on all Model 40s, but prepare to be proved wrong about any Avometer assumptions!

I agree that the temperature compensator is neater than the later model which always looks a bit rough and ready to me.

PMM

[The Philpott]

I hadn't spotted the radial cams on the switching of that Model 7- actually more pleasant to use than the later ones. What a find!
Dave

[Superscope]

Peter,

Surprisingly, part of the answer may already be in this Multimeter Survey.

We currently have Two Model 7's from 1936.
My one, and One from Forum Member Andy265, who only posted once in 2009 and never came back.
At least we know the older Switch design was in use.

We don't have any from 1937.
Now there's a chalenge if anybody wants to take it up!

We only have One from 1938, by Forum Member Pelham18 in 2017, but he only posted Four Times, (all on the Multimeter Survey)
and he never came back again.

However, the good news is, he did post a Photo of his 758-1616 Model 7.
You can find it on page 72, post # 1427 third attachment.

Looking carefully at the Photo, it is difficult to see, but I think it is definately the old style Switch being used.
What do you think?

So it would appear the old Style Switches were still in use up to 1938.

We have Six from 1939 recorded, and Five of them are from currently active Forum Members.
I don't wish to reveal which Forum Members have which Meters, but if they wish to
jump in at this point all the better, but at least One has mentioned the Switches are
the New familiar Modern Style.

From this, I think it is probably safe to say, the New Style Switch appeared in 1939, (maybe late 1938).
Possibly it co-insided with the launch of the Model 40.



Ian

[Superscope]

Dave,

We need your Forensic Analysis of the Photo on page 72, post # 1427 third attachment.






Ian

[The Philpott]

Ouch my eyes! The May '38 meter certainly LOOKS like it has the old switching..my June '39 meter has the new switching.

I had a theory that a shadow factory was involved around this period, so to confuse the matter there could POTENTIALLY have been a brief crossover where both systems were being issued... updated tooling may have filtered to the satellite factory after a delay.
(Pie in the sky, but feasible..)

Dave

[pmmunro]

This is a part of the photo on page 72, post # 1427 third attachment, with the balcks lifted.

It's possible to see the switch leaves on the right hand switch (parallel to the front panel, and the centre screw of the right hand switch cam, so it appears to be the newer switch style.

PMM

[Superscope]

Peter,

Yes, I think you may be right. Don't know what others think?

I guess that would put the change then, anywhere between late 1936 and
Mid 1938 then?

We will just have to wait for more pre War Meters to turn up.
At least ones where we can question the owners.

One thing I didn't notice before seeing your enhanced Photo, is the Ohms Board!
It's already moved to the position we are all familiar with between the Resistance Boards.

Obviously a lot of adjustments going on in the early Days behind the scenes
in the design department.


Ian

[Superscope]

I think the clincher, is the orientation of the Leaf Switches.




Ian

[Superscope]

I have just been made aware of an old Heavy Duty Avometer.

Turns out, for the second time in as many weeks, this is the oldest
of a particular type in the Survey.

155-448

What surprised me however, when looking at the Photos, is that it
doesn't have "Proterty of GWR" on the Scaleplate, which is what I
was expecting.

This one has "BR (W)" instead. So British Rail, Western Region.

Looking at our 1948 records, the previous oldest was posted on Page 38
Post # 754 of this Thread. Serial 159-448
It is exactly the same, with "BR (W)" and it's the same Colour.

Seems the very early ones might have been Silver/Grey Hammered finish,
unless this was a special small batch.


The really interesting thing here, is the Mention of British Rail which of course
had only just been created, and then a brief period where GWR was mentioned.

It looks like there might have been some Political infighting going on in trying
to keep their Identity.




Ian

[Phil G4SPZ]

Originally Posted by Superscope

Your Model D is interesting being built on a Model 7 Front Panel.
Not seen this before.

I've got a Type D here, built on a Model 7 front panel. I confess to having given up trying to get it working, as I could never reconcile the range resistances with the 1mA movement sensitivity.

If anyone would like to take it on, it's free for the cost of postage...!

[The Philpott]

Ian may want it Phil, but if not i could have a bash at it and return it to you if repair successful!

Dave

[Phil G4SPZ]

Originally Posted by The Philpott

Ian may want it Phil, but if not I could have a bash at it…

Hi Dave. I received a PM from Ian, who said virtually the same thing but with the names reversed!

I shall be delighted to post the meter to either of you, but please agree between yourselves who wants it… I don’t think it’s a basket case, but it needs work. As far as I recall, it was given to me by Paul Adams and I’ve no idea of its past history. The movement is 1mA FSD and it has the Type D scale. I have undertaken some work on it, but too far back to recall what I did. It’s probably the only Avo restoration that I didn’t complete successfully, so I hope one of you will be able to conclude the matter.

Here are some pics taken today. The bit of red tape is holding the Q knob in place; I don’t think the Type D had a Q knob, just a fixed button?

Ian, thanks for your PM to which I’ll respond in more detail in due course.

Phil

[The Philpott]

Yep, Model D had no Q knob function- didn't stop people trying to turn it, with predictable results!

I think Ian should have a go at it Phil, and he'll certainly let us know how he gets on.

Dave

[Phil G4SPZ]

Yes, okay Dave, many thanks. I’m just about to write back to Ian and I’ll arrange to get it sent off to him.

Cheers!

[Phil G4SPZ]

Ian, you have a PM.

[Superscope]

Hi Phil,

Ok, I will happily take on the Challenge of getting this Hybrid into some resemblance of working order.

Actually, a Type D with Model 7 enhancements, might make an interesting Avometer. A type D with a working Q Control maybe?

Or a Model 7 with Type D ranges, might be more accurate.

Thanks Dave, challenged accepted, but I might be asking for your input.

I will have a think of the best way forward and start a new Thread on it in due course.


Phil,

I did start replying to your PM, when my Laptop decided to crash on me mid reply.
I think the Power lead was loose.
Will re-reply shortly.


Ian

[pthomas]

My list of pristine working Avometers:

Avometer 9SX Test Set Steel Clad. Serial No. 817-15-361 Part 13574-5 Type 5QP/17447 (this version does not have the fuses in the battery compartment)
Avometer 8 MKIII. Serial No. 24789.965
Avometer Heavy Duty. Serial No.5892-1069
Avometer 8 MKII. Serial No. 97588-C1059
Avometer 8 MKI. Serial No. 41354-C-1255
Avometer 7 MKII. 83298-A-160
Avometer 8 MKII. Serial No. 56847.467
Avometer Model 40 Part No. 3284-149 (No Serial Number on Dial)

I have quite a few Avometers as shown in in photo plus a few of the storage cases. Its amazing that these are quite accurate to <1% and are usable. I keep them as museum pieces (batteries removed!) but I occasionally take one out of storage and check it. I have owned the 8 MK5 and MK6 but sold them since they do not have the same appeal as the older models. Although there is a fair bit of technical information on the internet I cannot find much about the Avo factories and the people who worked there. It would be great to find out more.

[micheal]

A DC AVOMINOR 5819-123 (December 1933) 89years old and almost in mint condition and the only thing wrong was dirt in mvt gap and the bearings needed adjusting, remarkable.

Mike

[The Philpott]

Thankyou pthomas for the serial numbers (something tells me you are into photography also!) i agree about later avometers- i have nothing more recent than a Model 8 MkIII, anything later from the company doesn't appeal.

Micheal, i also have a very early DC Avominor from 1933, i'll reiterate the s/no tomorrow for info. It functions (well the pointer moves) but the mvt is gritty- probably debris or damage.

Dave

[GroovyG]

re. my post #2720 of 2/11/20, I've just spotted what's probably the s/n of the Multiminor Mk5: 009701.

Graham