13th Apr 2019, 5:27 pm | #2101 |
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Re: AVO Multimeter survey
Re. Post No.2100- That was my thinking exactly! June 1939?
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13th Apr 2019, 8:42 pm | #2102 |
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Re: AVO Multimeter survey
I have one exactly like that model 5 with "plastic" screws
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23rd Apr 2019, 1:07 pm | #2103 |
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Re: AVO Multimeter survey
Another one for the record.
Model 40 Mk.2 No. 512 - B- 1266 Metal case (Silver, very similar to the Quad 11valves amps.) Complete with probes in wooden box, looks to be original with thick grey white felt padding. Any idea on year of this one from above numbers ? Photo later. Mike. |
23rd Apr 2019, 5:28 pm | #2104 |
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Re: AVO Multimeter survey
December 66?
Not so sure the box is original.
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24th Apr 2019, 8:53 pm | #2105 |
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Re: AVO Multimeter survey
Andy Gilham has contacted me regarding his Model 7 serial number 15629-A-550 which was made in the same month as my example, 15217-A-550. I’m attaching a few pictures of my meter here, in case they may also be of interest to anyone else.
I’d just like to point out that I bought this meter in good faith on eBay and did not ‘liberate’ it from the original owner! The company name appears to have been moulded in at the Avo factory. Phil
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Phil Optimist [n]: One who is not in possession of the full facts |
24th Apr 2019, 9:21 pm | #2106 |
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Re: AVO Multimeter survey
Thanks for the images Phil, looks identical to mine....as one would expect! So no repair mods there!
I got my Mod 7 for £20, and it pretty good condition. I will get some images. Phil, During the 50's and 60's, Avo were supplying movement assemblies to Marconi, that were used in their own equipment, I wonder if that same movement was used in The Model 7 you have. I'll need to investigate the differences from the standard Avo movement. Andy |
24th Apr 2019, 9:43 pm | #2107 |
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Re: AVO Multimeter survey
Ah, so you didn’t spot the two modern resistors in series that I fitted to replace an open-circuit resistance range winding?
As far as I can see, Andy, the movement is no different from normal. The serial number “15217” appears in pencil on the rear of the scaleplate, but there’s a different five-digit number on the back of the magnet assembly. I’m not sure you can see it in the photo, but it reads “46305”.
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24th Apr 2019, 10:25 pm | #2108 |
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Re: AVO Multimeter survey
Ooh yes I think I see them, just below the wound coils!!?
I also like the fact that these instruments have a tiny little extra shunt board added in. Ok so maybe it is standard. I will look into the archives. Andy |
25th Apr 2019, 7:30 am | #2109 |
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Re: AVO Multimeter survey
I have seen an additional oblong moulding that fits to one end of the meters, to carry the probes. Were these an optional extra , or only fitted to some models. Do they turn up on auction sites?
Given or loaned a pattern, I could mould new ones easily I believe. Can someone post a photo of one please. (Front and rear view.) Mike. |
25th Apr 2019, 10:54 am | #2110 |
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Re: AVO Multimeter survey
I couldn't resist rescuing an Avo 8 Mk5 at £1 from the inaugural TNMoC electrojumble at the weekend. Marked as faulty, the needle did move but stuck mid-scale. On opening it up I saw that the magnet centre pole was definitely not centred. A gentle lever with a non-metallic screwdriver remedied this. It must have taken a good knock but suffered no cosmetic damage.
After a couple of days of gentle to-and fro exercise on the movement using a function generator at 0.1Hz all is moving smoothly once more. The initial slight errors in returning to zero are virtually gone. I have re-attached the ripped-off battery connections and only have the 1x ohms range left to fault-find. Otherwise it's about 0.5% low on readings - not bad for £1! Avo 8 Mk5 Serial number 99842 Marked 8V/11/73 so Nov 1973 I assume. -Jeremy
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25th Apr 2019, 1:20 pm | #2111 |
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Re: AVO Multimeter survey
As promised, please find attached a few pics of my latest Avometer Model 7 (May 1950). this was the early model 7 panel that incorporated the PF sockets. Notice the small sub-pcb with the 20k ohm PF resistors fitted.
Andy |
25th Apr 2019, 1:30 pm | #2112 | |
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Re: AVO Multimeter survey
Quote:
Interstingly, although the same model made in the same month, your top resistance board seems to only include 3 wound coils, whreas mine has 4, or is this where your resistor modification comes in, is it a replacement for that coil? Andy |
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25th Apr 2019, 2:36 pm | #2113 |
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Re: AVO Multimeter survey
It's always intrigued me as to whether these early ones with the PF sockets are still a Mk1 or a Mk2?
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25th Apr 2019, 3:41 pm | #2114 |
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Re: AVO Multimeter survey
I consider them a mark 1, but it was clearly a transitional period. The front panel plug and instruction plate both states Model 7......so lets go with that!
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25th Apr 2019, 4:05 pm | #2115 |
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Re: AVO Multimeter survey
Indeed, the Mk1 terminal posts and as you say, it says Model 7, not 7 Mk2.
So Mk1 it is!
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25th Apr 2019, 6:09 pm | #2116 |
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Re: AVO Multimeter survey
I believe the PF sockets were an optional extra on the Mk.I
Dave |
25th Apr 2019, 9:28 pm | #2117 |
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Re: AVO Multimeter survey
Possibly, but not an option many user went for! Not seen a lot of these variants about, with the model 7 panel. I have a feeling the mould tool was modified to include the extra sockets, but near the end of its life, prior to the mk 2 being launched. Then it was a new panel with fully incorporated PF sockets.
Andy |
25th Apr 2019, 9:44 pm | #2118 | |
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Re: AVO Multimeter survey
Quote:
EDIT: I actually posted the serial number of this meter on 25th February 2008, right back on page 6 of this venerable thread! I think it may have actually been the first Avometer I acquired. Looking through some old closed threads, I now remember a bit more about this meter - the movement was faulty, due to the acceleration cut-out having come detached from the moving coil. I think it took me a couple of years to get round to it, but I eventually succeeded in repairing the movement. I wrote a Success Story about it at the time. The one open-circuit bobbin was the least of my problems!
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Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 25th Apr 2019 at 10:00 pm. Reason: Update |
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25th Apr 2019, 9:50 pm | #2119 | |
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Re: AVO Multimeter survey
Quote:
So there are at least three of the 7 and 40 models for an essential collection.
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26th Apr 2019, 9:04 pm | #2120 |
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Re: AVO Multimeter survey
Photos showing pristine inside views of my Avo re. my post of 23rd. this month.
Battery terminals needed cleaning, but don't they always !! Mike. |