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Old 29th Nov 2004, 8:36 pm   #14
pmmunro
Octode
 
Join Date: Jul 2004
Location: Dundee, UK.
Posts: 1,797
Default Re: AVO Multimeter survey

Avometers Serial Numbers As I believe them to be:

This is based on much research and a little speculation but appears to conform well to the other known facts - examples are taken from actual instruments. Model numbers in brackets were not used by Avo or the The Automatic Coil Winder and Electrical Equipment Company (ACWEECO) as they were before about 1953. If you can add to or correct to this list, please let me know.

'The Avometer' (Model 1) 1923 -1927 six figures, e.g. 135923

DC Avometer, 13 range (Model 2) 1927 - 1936 four figures e.g. 1562, 3588

Universal Avometer, 20 range 1932 - 1933 (Model 3)
M(M)Y XXX, where M is the month and Y the year within the decade. e.g. 13-919 January 1933, ser. no. 919

Universal Avometer, 34 range Dec. 1933 to June 1934 (Model 4) - As for 20 range Universal (speculative no example available).

Universal Avometer, 36 range (Model 5) 1934 - 1939
As for 20 range Universal

Later DC Avometer, 22 range (Model 6) c 1935 to 1939
Unknown, believed to be as for 13 range DC Avometer.

Early Model 7 Aug 1936 to 1947
7M(M)Y XXXX e.g. 729-2613, February 1939, ser. no. 2613

Early Air Minstry Spec 'D' 10A/10610 as for 20 range,
e.g. 39-8232, March 1939, ser. no. 8232

Model 40, original type, 1939 XXXX M(M)YY e.g. 2438-640
Serial no. 2438, June 1940

Later, early Model 40, as for Model 7, e.g. 404941-543, ser. no. 4941, May 1943

Admiralty Pattern 47A, 48A, XXXX-M(M)YY
e.g. 9299-842R ser. no. 9299, August 1942 - suffix possibly variant or production plant?


Later Air Ministry Spec. 'D' 10S/10610,
DXXXX-M(M)YY, e.g. D1631-241, ser. no. 1631, Feb. 1941

All models from c. 1947 to 1973, XXXXX-V-M(M)YY,
e.g. 656-B-248, Model 40, serial no. 656, variant B, Feb. 1948 (Variant B of the Model 40 does not have reverse AC overload protection diode across movement and has modified swamp coil).
Air Ministry Model 'E' is an exception, e.g. E349 1954
Serial no. 349, made 1954.

After 1973 to date
Serial No./Type/M(M)YY, e.g. 92936 8V/7/73

Model 8 Mark V, serial no. 92936 July 1973
with variants which even Avo can't explain.

As you will gather, I don't have a 34 range Universal or a 22 range DC Avometer, but I am interested in acquiring them.





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