AVO Multimeter survey

[AndyGilham]

Aitor,
Essentially the outer pointer is a feeler mechanism. The reading is made and the internal movement needle moves across the scale as normal and is held held in its position. The user then carefully and manually moves the feeler across the scale, until he/she feels a stop point (that aligns with the positional reading). From there, the reading can be made on the Braille plate.

[Aitor Eneko]

Ok, I see, the outer pointer moves free, is a very simple mechanism then. Not very accurate in my opinion.

I think it is an important model in any serious Avo Collection.

Avo Braille related: I just have two QSL cards (same card but 2 different radio stations) made to advert the Avo braille model 7. Never see one of Avo 8 or 40.

[AndyGilham]

It is quite basic....but it worked!!

Those are the QSL cards you scanned and sent to Richard of Richard radios fame? He did mention them to me. Nice find!

[Aitor Eneko]

Yes, they are. i find both in Spain, one of them with a Spanish radio Station indicative, so i assume Avo 7 Braille was sold here.

[Sinewave]

I don't have a braille meter in my collection, I couldn't see one.

[Aitor Eneko]

This is the other one, with a radio amateur station from Spain

[Aitor Eneko]

It seems that everybody are on holidays!!

My last Avo

It is a very old Avo 7 with serial 7109-3262 metal black case, no PF, metal zero screw.


Made in October 1939.

[Sinewave]

I've recently come into quite a few of the small hand held moving coil Avo's. I'll have to put the numbers up.

[AndyGilham]

Please find attached a few serial numbers. These were taking from a list of instruments all produced at the same time and used for product testing. Unfortunetly, not many had dates against them.


8Mk5 01024 Feb-89
8Mk5 01038 Jul-89
8Mk5 01239 Jul-88
8Mk5 02538
8Mk5 03116
8Mk5 03500
8Mk5 03508
8Mk5 04439
8Mk5 05950 Feb-89
8Mk5 06124 Aug-88
8Mk5 06294
8Mk5 08591
8Mk5 08594
8Mk5 020409
8Mk5 028903
8Mk5 029733
8Mk5 029822
8Mk5 030571
8Mk5 030576 Mar-89
8Mk5 030717
8Mk5 030846
8Mk5 030881
8Mk5 030957 Jun-88
8Mk5 030963
8Mk5 030979
8Mk5 032314
8Mk5 038043 Aug-88
8Mk5 038308
8Mk5 0547506 Feb-89
8Mk5 527568
8Mk5 530453
8Mk5 534654
8Mk5 538172
8Mk5 538467
8Mk5 539153
8Mk5 545003
8Mk5 545194 Jan-89
8Mk5 545477
8Mk5 545807
8Mk5 545859
8Mk5 545903
8Mk5 546013
8Mk5 546980
8Mk5 547056
8Mk5 547070
8Mk5 547174
8Mk5 547203
8Mk5 548253 Jul-88
8Mk5 548427
8Mk5 548434
8Mk5 548446
8Mk5 548475
8Mk5 548602
8Mk5 548612
8Mk5 548625
8Mk5 30116
8Mk5 43566
8Mk5 3849 Feb-89
8Mk5 527334
8Mk5 1012 M90845
8Mk5 1013 M50476
8Mk5 1018 M90286
8Mk5 1032 M50476
8Mk5 1057 M90219
8Mk5 1084 M90219
8Mk5 1091 M90286
8Mk5 1175 M50476
8Mk5 1203 M90219
8Mk5 1208 M90219
8Mk5 1224 M90219
8Mk5 1260 M50476
8Mk6 1044 M928230 1991

Andy

[Aitor Eneko]

Thanks Andy!!!

[Sinewave]

Serial number/part number? Hmmmmm...

So, some may recall earlier in the thread, possibly even this year or late last year I posted a query regarding the serial number of a model 72.

Some of these small hand helds like the 71, EM272 either have the number stamped on the scale plate or a sticker on the housing of the meter.

My 72 had nothing, other than a part number 5170-853. So we believed that was simply a part number of the movement/scale and that the serial was missing somewhere.

I've received another 72, again nothing on a sticker or stamped. So out of curiosity I check the part number written on the bottom left of the scale which is 5170-206.

So 5170 the part number?

853 and 206 the serial numbers?

Both scales are the same and I can identify each different unit by 853 and 206.

[AndyGilham]

sinewave, I can tell you that both 5170-853 and 5170-206 are part numbers. The first 4 digits defined the part category.
5 - A designed part
1 - An A4 drawing
7 - sheet material
0 - sequential number.
The last 3 digits are also sequential.

I was taking out part numbers in the 5174-xxx range back in 2000. I will up those numbers tomorrow for the scale plate. They must be mechanically different.... I shall have a look!

Andy

[Sinewave]

Interesting. Any idea on why both units do not have serial numbers? There isn't even any evidence of a missing sticker.

[AndyGilham]

Sinewave
I have had a look through my archives, but no sign of 5170-853 or 5170-206. I know i have them in Microfilm form, but i waiting to have those 75,000 films scanned..... it its approved (£15,000 job).
I have no idea why the instrument lack any serial numbers. I have a number of model 8 of different varieties that do not contain any serial numbers. I assumed these were used for engineering testing......maybe some of those type of instrument got out in to the big wide world!

[jez_145]

Some more AVO Meters for the survey list:-

Model 9 Mk II - serial no 13799-568

Model 8 Mk V - serial no 01384 8V/11/73

Heavy Duty HD5 - serial no 14714-379
certificate of test dated 28-Mar-1979 and signed by HJ Poole


Jerry

[The Philpott]

Avometer Model 40
s/n- 18664-747

[mark2collection]

The first two meters are my own, the MKII I bought between Christmas and New Year 2018, a brief write-up here:- https://www.vintage-radio.net/forum/...d.php?t=152626 and possibly the most interesting out of the three Avo's pictured, as it appears be a January 1956 MKII, so quite early.

The second Avo is a Test Set Number 1, bears an NSN (Nato Stock Number) with brown/reddish Bakelite, as opposed to the MKII & MKVI's black bakelite/black plastic respectively. The meter has the metal backing and came with it's original instructions plus replacement leads. This was given to me by my then-manager, some 20 years ago. This meter also has the BLR121 battery converter, part number 5210-064, allowing me to use either a BLR154/V74PX/10LF54 15V battery, but since these are getting harder to find, 10x AG10's in heatshrink fit nicely.

The third meter, a MKVI, currently belongs to the company I work for, and has only recently gone out of UKAS calibration. I've been told on numerous occasions to either bin it, or take it home!

Fear not, it's currently in cupboard, under my own lock & key, used occasionally at work. Am contemplating rehoming this meter and replacing the red (rubber) markers behind the 'meter cut-out' & 'Rev MC'.

Serial Numbers:-

Avo 8 MKII 43148-C-156
Avo 8 Test Set Number 1 8048.570 (NSN 6625-99-105-7050)
Avo 8 MKVI 3031M90285 4/86

All meters were tested against calibrated instruments on Tuesday, all are in spec

Mark

[AndyGilham]

Mark, I certainly recognise the BRL121 converter (5210-064), because I am sure I modelled in solidworks (3D cad software) probably 10 years ago....I might look into getting it 3D printed

Andy

[Sinewave]

I just love a day out!

I went out yesterday, came home with these goodies!!

I have no restraint and despite already having some, I picked up a Model 40 Mark 2 and a Model 8 Mark 5.

But, two of a kind which are new to my collection are

Avo All Wave Oscillator (working order not yet known)

and

Precision Avometer, which is working.

[The Philpott]

The precision avometer has a clever interlock mechanism to select which measurements are being taken, with the central position locking the movement for transit. If i remember right, it's 1000ohm/dc volt. No temperature compensation, the operator does the maths himself based on the formula written in the lid. Resistance ranges not included. Switching problems are easily remedied- simply because the switches and contacts are very accessible. Don't keep that one in the garage!

Dave