4th Sep 2017, 6:43 pm | #1461 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
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Re: AVO Multimeter survey
Those Aluminium cases are typically quite stiff. My favoured method is carefully picking out the rubber gasket with a jeweller's screwdriver, a bit at a time, and removing it altogether. This gives room for a larger flat blade screwdriver to be inserted and turned at various (and opposite) points around the periphery. Creak, creak, creak, creak, twang, it's off. This method has the advantage that it tends not to damage the aluminium.
A pp3 is ideal for the high resistance range, just don't use polystyrene as a spacer as it eats PVC. |
5th Sep 2017, 9:20 am | #1462 |
Pentode
Join Date: Dec 2002
Location: Norfolk, UK.
Posts: 168
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Re: AVO Multimeter survey
i have always used the method suggested by The Philpott but see he has beaten me to answering your query. I have found it often helps to clean up the edges of the aluminium and apply a little vaseline before putting it all back together.
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Richard |
5th Sep 2017, 9:29 am | #1463 |
Heptode
Join Date: Nov 2009
Location: Scarborough, North Yorkshire, UK.
Posts: 507
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Re: AVO Multimeter survey
Thank you The Philpott and Barnmead, I could use a wide thin wood chisel,I'll have a go this morning. One other thing, some of the white marking on the switch knobs such as volts/amps etc has disappeared, what do you recommend as replacement? Ted
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5th Sep 2017, 9:32 am | #1464 |
Pentode
Join Date: Dec 2002
Location: Norfolk, UK.
Posts: 168
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Re: AVO Multimeter survey
Whilst here thought I would submit these two for the database:
model 7 with side label 23416 7/12/70 model 40 mk2 13071-8-956 serviced and sealed by AVO in replacement casing with AVO Thorn Dover instruction plate Both complete with rubber bungs on front panel sockets.
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Richard |
5th Sep 2017, 9:35 am | #1465 |
Pentode
Join Date: Dec 2002
Location: Norfolk, UK.
Posts: 168
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Re: AVO Multimeter survey
i use off white emulsion paint from an old sample tin. It is now quite thick so can be applied and wiped off before completely dry with kitchen paper moistened a little if needed.
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Richard |
5th Sep 2017, 5:07 pm | #1466 |
Heptode
Join Date: Nov 2009
Location: Scarborough, North Yorkshire, UK.
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Re: AVO Multimeter survey
After a bit of a struggle got the meter out of its aluminium box, all looked OK except a few particles of swarf on the magnet, which I remove with a bit of blue tack on a stick. I then removed the movement, cleaned the dial and glass, a tricky job had to be very gentle. I also applied a small amount of Vaseline on the tracks of R P and Q, then cleaned up the grubby front, all very smart. Can you now tell me which is the Positive of the 9 volt connection, I've located the series link when two 4.5 volt were used, but not sure which is positive as the old batteries was crumbling to pieces when I took them out. I wish to solder a pp3 lead and need to get things right. I've check that the small connection is the positive on a flat 4.5 volt battery but not sure which way round the batteries fitted originally. Also, OK about the white emulsion paint, I will give it a try. More later and thanks for the help so far.Ted
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5th Sep 2017, 5:12 pm | #1467 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
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Re: AVO Multimeter survey
I think there's a + and - moulded into the bakelite, same as on the 1.5v fitment. Might need a torch.
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7th Sep 2017, 9:47 am | #1468 |
Heptode
Join Date: Nov 2009
Location: Scarborough, North Yorkshire, UK.
Posts: 507
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Re: AVO Multimeter survey
Here I am again. As I said, I checked for the link which put the two 4.5 volt flat type batteries in series making 9.0 volts, all OK, then was unsure which of the other two was the Positive connection, to where I was to connect the PP3. It turned to be the lower one, opposite the + sing, upper Negative, pleased to say meter is now working on all ranges. Many thanks to all the contributors. Ted
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8th Sep 2017, 5:11 pm | #1469 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
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Re: AVO Multimeter survey
Excellent. It's just as well there are a lot of them about- otherwise if we kept mending them at this rate we could run short of broken ones!
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12th Sep 2017, 1:09 pm | #1470 |
Heptode
Join Date: Nov 2009
Location: Scarborough, North Yorkshire, UK.
Posts: 507
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Re: AVO Multimeter survey
I need a Positive binder post for an AVO 7 or 8 if any one has a spare for sale or can point me in the right direction, I've looked on ebay nearly correct, but not quite. The meter works well, but at some time some one has been a bit rough. Ted
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14th Sep 2017, 12:55 pm | #1471 |
Retired Dormant Member
Join Date: Sep 2017
Location: Adelaide, South Australia, Australia
Posts: 1
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Re: AVO Multimeter survey
Greetings from Australia
Another Avominor to add to the survey, No.U.61621 - 1143 I take the - 1143 indicates November 1943 which makes the meter 5 years older than me, cosmetically we both still look good.... But some signs of wear! The rear lid, in brass, is badly scratched, but shows the Air Ministry ACrownM Mark. Case has a broken corner, repairable, electrically sound but movement sticky, still pulling the odd magnetic piece of swarf from the gap, using the gummy end of a strip of 'post it' note. This will take time and patience, in small bursts of enthusiasm. The meter probably migrated to Oz in the early 1950's with a family from around Nottingham, passed down a generation but still in the family. Kind regards, Andrew |
14th Sep 2017, 6:35 pm | #1472 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
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Re: AVO Multimeter survey
Andrew i assume that is a Type H universal avominor with the acv/dc&ohms selector switch on the front..? The serial number seems too high for a Type E.
Got any pics? The 1143 does indeed mean Nov '43. There is a chap in the UK who 3d prints new feet for these meters. (yours are probably missing or worn out) Dave Philpott |
21st Sep 2017, 8:36 pm | #1473 |
Pentode
Join Date: Oct 2016
Location: Dover, Kent, UK.
Posts: 235
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Re: AVO Multimeter survey
Interesting, I work for megger (Avo) as a mechanical designer, I have access to all historical technical drawings for Avometers, I have 3D modelling software and a 3D printer!!
I wonder how many people need spare parts!! |
22nd Sep 2017, 8:20 pm | #1474 |
Dekatron
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Location: Colchester, Essex, UK.
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Re: AVO Multimeter survey
Definite potential! I sent off a sample which became the template for the early universal avominor feet currently on sale. (The puffball shaped ones)
I haven't supplied a full sized foot as a sample for the full sized avometer yet but i think the material would have to be somewhat harder than the original article, since the original had what appears to be an integral textile backing to stop it sloughing off the rivet as the meter is lifted/dragged off the shelf. Might the technical drawings have details of the rubber foot profile... (if not i believe i have an unused one somewhere which would suffice...) |
25th Sep 2017, 1:47 pm | #1475 |
Pentode
Join Date: Oct 2016
Location: Dover, Kent, UK.
Posts: 235
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Re: AVO Multimeter survey
A couple of things.
As an employee at Megger Instruments (Formerly Avo), i can confirm that the company have no problem with forum member detailing the full serial number on the products. As you can imagine, we also have a lot of AVOmeters on site, and I will at some point get details of the various serial numbers. And of course, we have a lovely Model 1, which you can see here from our Megger 50 Open day. https://www.***********/photos/concer...57676777307135 I created the museum for the event. Additional, whilst browsing the 38,000 microfilms I had scanned, i have discovered some interesting AVOmeter data. Such as product build variations, discontinue dates and a few variants of very low volume products intended for special uses, such as the AVOmeter Heavy Duty 8 and the London University AVOmeter 8, with alternate ranges, and drawings for the Braille meter. I am like a kid in a candy shop!! Andy Gilham |
9th Oct 2017, 3:57 pm | #1476 |
Pentode
Join Date: Oct 2017
Location: Newton-le-Willows, Merseyside, UK.
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Re: AVO Multimeter survey
Hi Guys.
I'm Phil, I'm an electrician and have an interest in old things, being 52 you could say I'm getting old myself, but that doesn't mean I'm narcissistic, LOL. I found the article on old AVO's, and after reading it and several other interesting articles decided to join. I have seven old AVO's a couple of model 40's, a model 8 from 1963, three AVO Multiminor's and an AVO Minor.The Minor came to me after someone flytipped a load of rubbish outside a farm I do work for, they were clearing it up and out of a box fell this old meter, they didn't know what it was but saved it for me. The Multiminors came as follows, one was a gift off an old bloke some years ago, it had a bent needle, but I straightened it, the other two were offered to me by a lady who was clearing out her brothers house after he died. I had bought an AVO 8 from her, and she contacted me a week later to say she'd found two more meters, and would I be interested in them. they were both in cases, one in a traditional brown leather case, complete with warranty leaflet, and one in a black Nato case, complete with original leads, prods, and clips, all in excellent condition. The AVO 8 was also in a Nato case, and while it looks quite good, I think there is a problem with it on one of the ranges, the leads were also slightly perished. One of the 40's was purchased a couple of years ago and I did actually use it at work, the other one was purchased at the weekend, it was for sale locally for £25, with a very good set of leads, retractable prods, and clips. I bought it for £20, I only bought it for the leads really, it was cheaper than a set of leads off eBay. I've done a very neat conversion on one of the 40's, and it now uses a PP3 and a D cell battery, the others I plan to leave as original, I won't be using them. I will post up some pictures of them soon with the serial numbers. |
13th Oct 2017, 12:24 pm | #1477 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
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Re: AVO Multimeter survey
Phil i imagine you will find yourself using one of the others sooner or later- i find the low voltage DC ranges on a Model 40 restrict it's versatility quite a bit! I did have a mod in mind to give mine extra 48v,24v,4.8v and 2.4v DC ranges, but it was too good inside to justify messing with it's original design, also with the extra hassle of making a one-off instruction plate.
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13th Oct 2017, 12:46 pm | #1478 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,736
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Re: AVO Multimeter survey
Welcome to the hobby (or should that be obsession) of Avometer Admiration, Phil. Many of us on this section of the Forum started out by acquiring one, then another, then another... and then they start to be donated to you, and after a while you can't move for the darned things!
The Model 40 is great for electrical work, but as Dave says, not so brilliant for electronics. If you ever find an old 36-range Avometer (the predecessor of the Model 40) you'll find it has the ability to measure resistance down to 0.1 ohm, quite a useful feature. I only had one MultiMinor which I recently gave to a friend, but I began to admire its performance, and also found it compact enough to keep in the toolbox. Anyway, keep collecting and please post some serial numbers as and when you can.
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Phil Optimist [n]: One who is not in possession of the full facts |
16th Oct 2017, 5:30 pm | #1479 |
Heptode
Join Date: Nov 2009
Location: Scarborough, North Yorkshire, UK.
Posts: 507
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Re: AVO Multimeter survey
Please enrol another AVO. Went to Hornsea Mobile rally yesterday and spied a Model D looking for a home,number 9772-643 and bought it for £5. No battery, but case is clean, what battery does a Model D need/require and which terminal is Positive On the dial it says ASWEECO-LTD.The instructions on the rear are worn away, has anyone a copy or can any one make a practical suggestion. Also when on the Ohms K2 what is the resistance range ? Ted
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16th Oct 2017, 5:36 pm | #1480 |
Heptode
Join Date: Nov 2009
Location: Scarborough, North Yorkshire, UK.
Posts: 507
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Re: AVO Multimeter survey
Back again, forgot to mention a label on the meter said bought in Colombo in 1947. The top of the dial is mark A M, and below on the left B-S-F-G.Ted
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