AVO Multimeter survey

[SPCh]

Sam's right. If the zeroing pot gives erratic results ("can't hit the right spot")it's probably dirt; if it "won't turn quite far enough" it's probably the 1.5 volt battery (high internal resistance) or possibly corrosion on the battery contacts, or on the leaf switches m-n and h-j. Try several new batteries before going inside !

Thanks for the serial number.

[Merlin]

I have an AVO model 8
8xxxx-C-359

[Rob Lines]

Hello again SPCH. Further to my post at#117, more Avo details:

I have a 8 MkV in a plastic case, the ser no is on a tatty label, one on the side , one in the battery compartment, Ser No 48582 8V/12/74.
The problem with this one is that the mechanical zero on the front of the meter does not work, it appears that the 2 prongs of the fork are not long enough to keep the back end of the meter needle in between them and when the adjuster is turned fully in an attempt to zero, the back end of the needle slips out. Have you come across this previously?

I also recently acquired a Model 40, Ser No 407610 - 744, a year & a bit older than me. Seems to be in very good nick externally, with a bakelite front panel and a metal case in hammered silver finish. Serviceability not yet known but I have managed to remove the heavily corroded 4.5v batteries, no damage done, the 1.5v D cell is held in a modified holder. The top right hand of the front panel has a 3/4inch square smoothed into the ripples on which is engraved '6Bc TH' (inside a circle), with '5468 B.RD' underneath. There is a small metal plate screwed to the RH side which says 'Pool'.

Rob Lines

[johnlees]

I have a Universal Avometer Model 7 6XXXX-7475

[Superhet Si]

My old Avo 7 bought for me by an old girlfriend 12 years ago in Horsham Sussex.
Ser Nn 20476-A-1250
And My Avo 8Mk 5 scrapped by work due to 10 amp shunt open circiut is 08550-8V/5/77
Can you tell the dates from these codes?

[pmmunro]

Dates of manufacture -

Model 7 - December 1950,

Model 8 Mk V, May 1977

Send me a private message and I will see if I've got a 10A shunt - after the weekend.

Best regards,

Peter M. Munro

Hi there,

I have a model 8 - 11947.h.664.D
and an ex BBC model 7 - 66937-a-956.

Hope this helps.

[molochkartovski]

Mine's an AVO 8 mark V
Serial No' 09537 8V/5/78

Richard

[G4BZI Roger]

I have a Test Set Multirange No. 1 - looks like ex-RAF last calibrated in the mid-1970s.

On the bottom LHS of the scaleplate there are the following characters in the "ser. no." space: A.C.W./R 472 1094.

This meter would not zero properly on the ohms div. 100 range - this was cured by cleaning the contacts on the 1A fuseholder in the battery compartment.

Roger.

[SPCh]

Thanks for all the recent inputs and for PMM's fielding of them in my absence. I shall be back in circulation in a week or so.

Please bear in mind that this thread is for Serial Number exchanges only.

Any problems, fixes, or servicing issues should be posted in an appropriate (other) thread.

Those of you who wish to submit problem/solution PMs are welcome to continue doing so: I'm happy to consolidate them to avoid multiplications - particularly of popular mis-diagnoses and tenacious erroneous myths.

[optics42]

New here, so apologies if not the right place.

I have an AVO 8 with no obvious serial number plate. There is a number on the scale plate No. 27033-C-854.

It's in a rather sad state. It has obviously been dropped as there are cracks in the case radiating from one corner and the needle sticks.

...but it's available to anyone who would like to have it and is able to collect from SE London.

[SPCh]

Thanks for the input. It's a "stalwart" Model 8 Mk I from August 1954 - almost the middle of the product's lifetime. Hope you can find a good home for it.

[ramjet2uk]

Looked at the meter on mine. It has no. 7742-7900. It's an avo 7. Does this mean it was made on the ninth month 1900.? Its made of bakerlite..!

[SPCh]

No; sorry Ramjet.

It DOES have the distinction of being the earliest Model 7 in thesurvey to date.

Its serial number is 7900, and its date is July 1942. As this model was introduced in August 1938, the implication is that they'd been turning out about less tha 150 per month, pre-war. This went up to about 800 per month throughout most of World War II. As I've said before, given the labour-intensity of just calibrating these little darlings, who was left to do any fighting !!!

[3nf]

Avo Model 8 Serial 28482 C 1154

Bought reconned from Charles Britain Radio of Upper St. Martin's Lane W.C.2
on 13th Jan 1962 for 15 Gns. Set of leads cost 10/- , perished long ago.
Meter still works well.

Also: Avo 9 Mk II Serial: 13877.568. Makes a good doorstop.

[coil1234]

Looks like this thread may run and run,

2 AVOs Here;

AVO 8 mk 5 ser 08338 8V/3/79 owned from new

AVO 7 ser 18771-A-1050

as a sideline when a M*****i apprentice in the 70's I used to calibrate all the companys AVOs in the test equip dept. If I remember correctly the company had 500+ AVOs mostly 8 mk 2-4 these had a cal periodicity of 40 weeks if memory serves me well. I still have the hard skin on the inside of my fingers from rotating the knobs on the Fluke 760A Meter Calibrator ( excellent piece of kit)


Mike A

[ramjet2uk]

Hello again.! Interesting thread. Just pulled out my other Avo and it has on the meter "Type H.R.M" no. 632-1248. It is an Avo 7. not sure when it was manufactured.? these numbers are a little confusing.!

[pmmunro]

Ramjet,

It looks like what you have is a High Resistance Avometer - much rarer than a Model 7 and a type which could be considered the forerunner to the Model 8. (There are in fact two versions of the HR Avometer).

This fits with the serial number and the date of manufacture implicit in the serial number.

For more details, see a previous thread on Avometer identification.

Peter M. Munro

[Drifton]

Just pulled mine out of the skip today

Avo 8 - 34592 555

Which I if I'm right is May 1955.

AC and DC works fine but nothing from the Ohms side. The 1.5v battery (Vidor) reads 1.3 and the 15v (Ever Ready) 13.5, which I would have thought, would be enough to shift the needle. So I suppose that means it's zapped.

All four terminals are black (no red one) and are solid with no plug socket in the centre.

Cheers,
Dave

[Brased]

Another one for the list. An early Model 8 No. 84748-C-159.

Edward