AVO Multimeter survey

[Superscope]

Thanks Owen,


Welcome to the forum.

Always great to hear of Avo's down under.



Ian

[theredhouseinn]

Hi all AVO enthusiasts.
I have 3 Model 8's
MKIV serial no. 47115 84/6/71
MKV serial no. 47663 8V/11/74
MKV serial no. 07279 8V/6/76
I have used AVO's since 1957, I would never contemplate using anything else for faultfinding. It's in the blood.
John.

[The Philpott]

There's a regular 'field auction' near me that occasionally has electrical curios that you may be interested in John, Longfields Auctions. An awful lot of hideous chairs and old bicycles abound, but you have to look beyond them..That's where my first Avo came from. (The next one came out of a skip!)

Dave

[Barnmead]

re post 2808

I can now advise that the screw threads on the probes and clips are 2BA

[MIKEG4IIA]

Where else, apart from on the scale plate would I find the serial no? Can't find it on one of four I have.

[theredhouseinn]

Hi Mike
The serial number on my MK4 is on a faded sticker on the side of the case. I need a bright light to see it.
John.

[Superscope]

For the Full Sized Avo Meters, Serial Numbers were always written on the
Scaleplate until 1970.
On the Lower Right Side for the commercial Meters, and on the Lower
Left Side for the Military 9sx / TSMR No1.

From January 1970, Avo started to put the Serial Numbers on Stickers
on the Right Side of the Meter Housing instead.
This was for all Models (7,8,9 & Model 40).

For the Model 8 Mk V & VI the Sticker was often but not always
repeated inside the Battery Compartment.
With the Model 8 Mk V, the Date Code was often omitted for some reason.
The Model 8 Mk VI and early Mk VII often had a separate Date Code Label.

If the Serial Number is missing, the Sticker has either been removed
(Can't imagine why ), or the Scaleplate/Movement has been replaced in
previous repairs.
Avo normally re-wrote the Serial Number on the New Scaleplate, but this
wasn't always done, probably when a Third Party Repairer did the Work.

If your lucky,
Missing Serial Numbers can sometimes be found inside the Meter, often
written in Pencil by repairers on the back of the Scaleplate.
For older Meters, Serial Numbers were often written on the Horse Shoe
Magnet or the Magnetic Shunt Bar.

Ian

[Top Cap]

I have an old Model 8 Mk.II which has been collecting dust for many years. It has the name Bruce Davies embedded on the front. I acquired it along with other stuff at a local auction, I did know a Bruce Davies who worked at G.E.C. Marconi Avionics many moons ago, perhaps he passed on and his house contents auctioned?
It's free if anyone wants it but has to be collected from Garston, North Watford, close to Junction 5 of the M1. Last time I tried it the readings were all about 50% low on all ranges. But it might be useful if anyone wants a glass or cabinet shell. Scale looks good, printed Model 8 No.117565-C-161

[The Philpott]

(Some of) the Marconi allocation of meters had a couple of small aluminium plaques glued to the base. If these have been removed it's sometimes possible to see the scrape marks and the 'ghost' of the plaque outline.

I have found that readings that are that dramatically low are typically down to a leaf switching problem- usually tweakable/fixable.

Dave

[ex 2 Base]

I have an AVO Bridge in a wooden box, stencilled on the box top, it says Bridges, Test AVO, No.1 MK 1 Equipment WY2438 and on the inner side it says Cases Test Equipment No.5 WY 2176 and on the meter scale plate 3007 - 244. The box has 6 wooden, felt covered restriction posts, to prevent damage when the meter is in transit. Inside is varnished and has that AVO smell. The outside of the box is painted deep RAF blue and the leads look to be original, a thick stiff rubber type material with large crock clips. A leather carrying handle and all is well made to I think military standard. Can any tell me about the date of construction or what WY 2176. Ted

[Superscope]

Ted,

I think the Construction Date follows the normal Avo Date coding.
So your Bridge will be Feb 1944.
It also fits in nicely with the Six Bridges we now have logged including yours.
Earliest logged Date we have is 1943 and the Latest is 1947.

Interesting you mentioned RAF Blue, I never thought about it being
RAF, but that makes sense.

Can you post any Photos of the Box, Leads and Bridge ?
And anything else included with it ?

Mine says Bridges Test, AVO No.1 MK II (Complete Station).
Would be interesting to know the difference between the Mk I and Mk II.

Inside it has the same Label as yours "Case Test Equipment No.5 WY 2176".

Mine didn't come with any Leads or accesories in the case, so I started a
Thread about it a couple of weeks ago, but only had one response from
TowerRadio (Les) who says the Box should have had a Spare Valve and
External Reference Capacitors in it. Sadly, mine are all missing.

I think a lot of these Bridges survive, but most don't appear to be in their
Boxes any more.

I incorrectly stated on the other Thread, that the Box is the same size as
the one used for the Admiralty Pattern 48A Avometer, but this isn't quite
true as it is very slightly smaller.

I am currently in discussion with the REME Museam about some other Military
markings, so I will ask about the Numbers on the Bridge in due course.

They are very busy at the moment, so responses are quite slow and they are
all volenteers as far as I know.

I'm looking forward to firing mine up and seeing if it works, but just don't have
the Time at the moment to wake it up carefully.


Ian

[Barnmead]

Two more for the database:
Precision avometer
313-1266
582-667

The MkII with blue Welwyn resistors rather than wire wound ones came along in 1970

[MIKEG4IIA]

Indeed I have a sticker. Thanks. OK, I have an AVO 8 with no indication of MK. Ser. No. 106017 1069 hand written on the scale. I inherited this when I bought my business in 1984.

My other one I bought through my employer at so much a week, taken from my wages, when I first started my radio, TV and audio servicing career in the early 1970's. It's a MK IV and the sticker is difficult to read but it looks like 64125 then 84/2/72.....the last 2 digits seem to tie in with my purchase year!

[valveaudio]

I have a Avo Minor it's Air Ministry (RAF) one, type H model 10S/46. Serial No.42494-941.
It probably has an interesting history as I bought it on a visit to Canada.
All working and still used occasionally, you can still read the instructions on the back, from what I have seen most of these meters have the instructions rubbed or corroded off.

Trevor

[Superscope]

I stumbled across an old Thread on this Forum earlier, which shines a
bit more Light on the Avo Test Bridge Launch Date.

https://www.vintage-radio.net/forum/...ad.php?t=94971

This now definately puts the Launch Date in 1939.
August or September seem likely.

So the Date of 1936 in the Restoration Manual is now highly unlikely.
The last example known about at the moment, is also from the
Restoration Manual and implies 1947.
So if anybody knows of one later than this, please let us know.

I notice the Meter Movement looks like it is from an AvoMinor.
I've not had time yet to measure the sensitivity.



Ian

[AndyGilham]

So this is in fact a Universal Avominor from September 1941.

1941 saw the swap over to raised socket rings on the front panel and a jump in serial numbers to signifiy this. They started the sequential numbering at 40000, so your meter was the 2494th meter of the line after the transition.

Andy

Originally Posted by valveaudio

I have a Avo Minor it's Air Ministry (RAF) one, type H model 10S/46. Serial No.42494-941.
It probably has an interesting history as I bought it on a visit to Canada.
All working and still used occasionally, you can still read the instructions on the back, from what I have seen most of these meters have the instructions rubbed or corroded off.

Trevor

[chamaragg]

Hi SPCh

1 AVOs here,

AVO 48A , serial no. 13769-244

Only meter.

Chamara Godagamage
__________________

[The Philpott]

Thankyou for the details Chamara, that is a Royal Navy meter from February of 1944.
Dave

[sparkymike]

I bought three yesterday for princly sum of £10.00 each. Two work and one has cracked case and does not work. Probably been dropped.
Photos below, hopefully showing serial numbers etc.
Will post seperately to avoid confusion.
Mike.

[sparkymike]

Second unit.