AVO Multimeter survey

[Aitor Eneko]

Originally Posted by Superscope

Thanks Mike,


For those interested, the Database now contains over 3000 serial Numbers.




Ian

Thanks !!

[Superscope]

Anyone else seen this style of Magnetic Shunt on an Avometer movement?

I've not seen one like this before.

Definitely an Avo movement, and no reason to think it is not
original to this Meter, a Model 9 Mk IV dated Jan 1970.


Ian

[The Philpott]

No, but what a simple solution. Looks like it needs the blu-tak derusting treatment
Dave

[Superscope]

It's not just the Shunt, the Magnets and pole pieces appear to be
welded together into a single piece construction.

I must have seen more than a Hundred Avo Movements by now, and
I don't remember ever seeing anything like this!

Sadly, it's OC, so is probably scrap, so the rust is the least of it's
problems.
Double sadly, that makes this Mk IV pretty much scrap as well

I might have a bash at repairing it, but I don't hold out much hope
to be honest.
It's a pity there just don't seem to be any Moving Coil repair experts
around any more.



Ian

[pmmunro]

That's definitely an unusual magnet assembly Ian. I haven't seen one like it either.

At Januray 1970, and being a Model 9 Mk IV, it comes from a time when there was considerable experimentation in an attempt to save on costs of production. However, it's quite likely that the Mk V design and its centre pole movement were in at least an early design stage at this time.

It might be worth checking where the meter's serial number comes in the Mk IV sequence, if it is decrenable.

PMM

[Pamphonica]

If it's a 9, then I might have a spare NOS movement, but I'm not sure exactly which mark they are. I have three still in their (battered) plastic protective cases. On test tonight, they are all showing slight signs of sticking when presented with a slow current ramp. If I get a good one after an overnight on my "exerciser", I'll PM you. The exerciser carefully causes the meter to move from end to end of the scale, at about 0.2Hz. A great use of a function generator!
The meter magnets are very conventional, by the way.
-Jeremy

[The Philpott]

My 'meter movement exerciser' is the top part of one of the old type (filament) road lamps, around 1Hz. Another member tucked a meter away in the boot of his car, linked it to one of the indicator lamps and drove to work and back for a couple of weeks!

Dave

[Sinewave]

I've got lots to add - on another note, is there another survey due? Hopefully later I'll get a load more added, I'll likely need to do an audit to see if I'm missing any entries.

[Pamphonica]

Ian (Superscope), PM me - I have a good smooth replacement movement if you think it will fit. The other two are still not right. One is smooth but sticks just below zero. The other is still jerky.
Photos show my meter exercising lash-up and the best movement.
-Jeremy

[Hybrid tellies]

Just added my Multiminor 4 to the list. Sadly no serial number found.

[barrymagrec]

I am now the owner of my Dad`s old Universal AvoMinor, serial U.62645-1243, sadly not in great nick as it was dropped from a high shelf circa 1970.

[Superscope]

PMM,

Nothing particularly special with the Serial Number unfortunately.
Apart from me needing a trip to Specsavers. It has Two "1's" not One.
So it's actually a November 1970 Mk IV.

There is another 9 Mk IV logged in the Survey with the same Date
and a very close number, posted about 10 Years ago, but it looks like
the Forum Member never posted or logged in again so it's not possible
to check if it was a Batch thing going on.


Pamphonica,

Thanks for the offer Jeremy.
PM sent.

barrymagrec,

Thanks for posting the Serial Number of the poor old Minor.
What parts are broken?
I might have some Spare parts for a Minor if I can lay my
Hands on them.
FOC just postage if I have the right bits.


Ian

[The Philpott]

Post 2931, 2932

Likewise Barry, if you want to try and resurrect it post a photo of the damage.
(Not sure i have the bakelite casing though, i would have to check)

Dave

[Superscope]

Regarding the unusual Meter Movement, there is a comment
in the Model 8/9 Mk IV Service Manual on page 18 which states:

"If magnet is solid grey type, Coil Assy. is 45469"

Solid Grey pretty much describes the movement here, so the fact
that a different Coil assembly was clearly available as a spare part
suggests that this type of movement was widespread enough in the
Mk IV for mention of it in the Manual.


Anyone willing to peak inside their Mk IV's I wonder?


Ian

[barrymagrec]

Universal AvoMinor

Thanks for your offers of help, I was moved to give it a quick check,the main obvious thing is that the glass is cracked and a piece has dropped and may foul the needle. Surprisingly a quick check on the 25 and 100 volt DC ranges came out somewhere close, I didn`t do any more as I`d really need to find wander plugs (I have them....somewhere).

I also had a look inside, looks O.K., battery contacts are in poor shape - always were from memory

My Dad wouldn`t have used this much after he got his 8 mkII in 1958 and I only used it a little in the sixties.

I may sort it out one day but not for a while, far too much other stuff to sort.

[Sinewave]

Some more for the log

Model 7 Mk1, Serial No. 7943-11771

Model 40 Mk2, Serial 2490-B-767-M

Model 8 Mk7, Serial 8060 1027 1193
Model 8 Mk7, Serial 1010 M534500
Model 8 Mk7, Serial M1396501016000601

[Riccardo Grillo]

Model 8 MkII, S/N 2XXX-C-563T

Already added this to the Google Doc, but it won't let me see the results due to 'file error'.

[Riccardo Grillo]

Originally Posted by Pamphonica

I will publish a link to an online summary spreadsheet once I have a few contributions.

Any news on that?

[sparkymike]

My daughter, who lives 240 miles from me rang me when she was at a car boot sale near Weston Super mare and asked me if I would like an Avo meter. Price was only £5.00 and I will not see it until father's day.
She sent photos on which can be seen the serial number etc.
Would this be 11/59 date ?
Mike.

[Superscope]

Indeed it is Mike. November 1959.
It will be a Mk II.

It will most likely have a Bakelite Case, but if by chance
it has an Alloy one, please let us know and the Colour it's
painted.
I now record those details.
Also the Battery Cover type.

£5 is a pretty good result even for a Model 40.
It looks in pretty good cosmetic condition.
Usual story, if the Movement is Ok, it should be straightforward
to fix if it doesn't work.

Still a very useful Device, just not on electronics.
More power orientated.
I tend to use Model 40's for monitoring Charge Voltage and Current
when playing around with Batteries.



Ian