2nd Jan 2019, 8:44 am | #1901 |
Octode
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 1,018
|
Re: AVO Multimeter survey
Hi Aitor,
The Circuit Diagram of the Test Tool I think you are looking for is attached. I built one of these, but modified it for use with both the older 1-12 Scales and the 1-10. Simply Circuit, but finding the 1 Ohm Resistors was a Task! Also, I think the 0.05% tolerance might be a typo! Impossible to find at this level! I settled for 0.2% which was the best I could achieve. Ian |
2nd Jan 2019, 9:08 am | #1902 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,735
|
Re: AVO Multimeter survey
Ian, that’s very interesting. However it does rely on the cell being able to supply over 100mA without its terminal voltage dropping at all throughout the duration of the test. What type of cell did you use?
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
2nd Jan 2019, 9:24 am | #1903 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
Thanks very much. I wonder that it could be better to use a power supply.
Why there are 2 variable resistors in series 20k and 100k?? |
2nd Jan 2019, 9:26 am | #1904 |
Octode
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 1,018
|
Re: AVO Multimeter survey
Phil,
Yes, you are absolutely correct. I cheated, my Circuit is running off a Regulated PSU for testing at the moment. It's actually not quite finished yet. As is so often the case, you start a project and get side tracked! The plan is eventually to run it off 2 x AA Cells (NiMh) and a Zener Diode to bring it down to a fixed 1.5 Volts. Got as far as fitting the Battery Box and it stopped there for a while. Ian |
2nd Jan 2019, 9:28 am | #1905 |
Octode
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 1,018
|
Re: AVO Multimeter survey
The Two Variable Resistors are for Course and Fine Adjustment
of the FSD. |
2nd Jan 2019, 9:57 am | #1906 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
Thanks, I suppose so, but I was thinking that only with a higher one perhaps will work fine
|
2nd Jan 2019, 9:58 am | #1907 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,735
|
Re: AVO Multimeter survey
Hi Ian. I think you’re probably taking the right approach by running the circuit from a regulated power supply. I’d do the same, unless you require portability. The reason I’m interested in circuits of this type is that I built a low-reading ohmmeter using similar principles. It worked fine using a D-size NiMH cell, but of course the duration of discharge is much shorter than with the cardinal point checker, which could be running for several minutes.
I presume from the high resistance values in series with the meter that Avo intended this circuit to be used solely for the Model 8. I’d like to build something similar that would test lower-sensitivity instruments with a similar degree of accuracy!
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
3rd Jan 2019, 12:29 pm | #1908 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
Today I finally received my 36 range Avo. Serial number 26-5007
|
4th Jan 2019, 5:28 pm | #1909 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
Avo 7 mk2
226-A-1061-F With PF connectors |
5th Jan 2019, 6:31 pm | #1910 |
Octode
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 1,018
|
Re: AVO Multimeter survey
Ladies and Gentlemen,
Happy New Year to you all. It's been a long time coming, and it's not finished by any means, but please find attached a more complete version of the AVO Multimeter Survey Data. I have no idea if this is even close to what SPCh envisaged back in 2004 when this Thread was started, but I hope it will be of interest to some of you. It is still my intention to improve on the Data recorded, in particular Case Styles which has popped up several times recently, but I can't do this unless the Data is still coming in. Please feel free to comment (Good or Bad) on the Document, and offer any suggestions for improving it. There are a few more Meter Types that will be added shortly. So, we are still looking for New Serial Numbers and Case details for Model 7's/ Model 40's and Model 8/9 Mk IV's even if their Serials have already been recorded. Ian |
5th Jan 2019, 6:46 pm | #1911 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
Fantastic job. congratulations, it is easy to see the production month after month. Very useful and important this job!!!
|
5th Jan 2019, 7:57 pm | #1912 |
Nonode
Join Date: Mar 2008
Location: Virginia Water, Surrey, UK.
Posts: 2,872
|
Re: AVO Multimeter survey
Ian, what an absolutely fantastic job you have done. That's a real labour of love and a superb record for posterity. My thanks for all that hard work.
Is it possible that the last two entries for the Model 4 are actually the same meter? And is the blurring of the data (looks like a picture import) deliberate, to stop scoundrels stealing it? If so, what about a good strong watermark all across the pdf? Since your post containing the pdf document might become lost in the hugely long thread, could the moderators somehow link to it in the very first post? Great job. Jeremy
__________________
Jeremy, G8MLK, BVWTVM Friend, VMARS, BVWS Secretary. www.pamphonic.co.uk www.bttt.org.uk |
5th Jan 2019, 8:44 pm | #1913 |
Octode
Join Date: May 2017
Location: St Austell, Cornwall, UK.
Posts: 1,018
|
Re: AVO Multimeter survey
Hi Jeremy,
Thanks for the comments. Yes, the last Two Model 4's are the same Meter. Dave's one as I recall. It's one of those many things that slip through the Net, no matter how many times you go through the Data. It was reported twice in the Thread, so it slipped through. Quite a few Meters have been reported more than once over the Years. You might notice only 3 Model 4's are shown in the Stat's at the end. The List does show up some interesting things. There appears to be another duplicate Number on the Model 7 Mk II. Identical, but one states it's Braille. These were reported by different Forum Members and I can only List the information given. Regarding the resolution, no, it wasn't a deliberate ploy to stop copying, it was simply a result of the way I was importing Data between Applications. I decided it was good enough for the time being. I hope to improve this on the next edition when I change over completely to Linux Applications. The low Res was actually a surprise because I have been using all Microsoft Software up till now for this Project. Anyway, it's great that errors are being picked up on, and I encourage that. Aitor has already highlighted another small error to me which has been corrected on the Master Database. There are a few errors on it that I know about and will correct going forward, but I am happy to answer any questions if anybody has any queries and more than happy to have errors highlighted. It's a Working Document after all. Ian |
5th Jan 2019, 9:16 pm | #1914 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
|
6th Jan 2019, 2:25 pm | #1915 |
Pentode
Join Date: Dec 2002
Location: Norfolk, UK.
Posts: 168
|
Re: AVO Multimeter survey
Thank you for embarking on a mammoth task and producing such a useful result. I see that item 16 is listed as a model 2, this is incorrect (my fault) it should be the rarer model 6 see here: http://www.richardsradios.co.uk/avo6.html
__________________
Richard |
6th Jan 2019, 3:51 pm | #1916 |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
One more!. I think is not on the list, is not of my property, i found it on a electricity forum i think.
Model 8 serial number 96084-C-959 |
6th Jan 2019, 9:06 pm | #1917 |
Pentode
Join Date: Dec 2018
Location: County Meath, Ireland
Posts: 242
|
Re: AVO Multimeter survey
Just received mine, Model 8 MkIII No.25xx.666 the mark of the beast!!!
|
7th Jan 2019, 1:16 am | #1918 | |
Guest
Posts: n/a
|
Re: AVO Multimeter survey
Quote:
Thanks Aitor Eneko |
|
7th Jan 2019, 9:36 am | #1919 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,735
|
Re: AVO Multimeter survey
Ian, I’d like to add my thanks for your hard work in preparing and sharing the survey results. It is a superb work of reference and will be valuable to all of us who share this strange affliction!
One thought on the reason for duplicates - there may be meters that changed hands during the currency of this thread and were reported by multiple owners.
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
7th Jan 2019, 12:17 pm | #1920 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
|
Re: AVO Multimeter survey
Seconded, well done Ian.
Aitor, i took a photo of the steel guard/helmet in the Precision Avometer, i will find it. Dave |