8th May 2020, 10:59 pm | #2521 |
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Re: AVO Multimeter survey
I’d love to own a VC1 Dave, but one has never cropped up inside any Avo I’ve acquired! I have always wondered how they work, though. There is no input switching, so I assume the inverter imposes a continual drain on the D cell. Presumably this is miniscule until a resistance measurement is actually being made. Does the VC1 come with instructions or any information about how the life of the D cell is affected?
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9th May 2020, 7:44 am | #2522 |
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Re: AVO Multimeter survey
I've not measured the Current Draw myself, but there is a nice Write
up of the VC1 on the Richards Radios Website. http://www.richardsradios.co.uk/vc1.html I did search for a VC1 Schematic and other Documentation in the past, but Documentation for it seems rarer than the VC1 itself! Ian |
9th May 2020, 9:20 am | #2523 |
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Re: AVO Multimeter survey
Thank you for that link, Ian, very interesting and everything I ever wanted to know about the VC1! A quick calculation shows that the VC1 will drain the D-cell within about 5 years at worst. Hardly a problem, but if you have one of these permanently in circuit inside an Avo in your collection, it is worth putting a note in your calendar to check it every now and again.
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11th May 2020, 6:57 pm | #2524 |
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Re: AVO Multimeter survey
There was a post about the VC1 some time back from Dekatron
https://www.vintage-radio.net/forum/...d.php?t=158281 Andy |
17th May 2020, 10:14 pm | #2525 |
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Re: AVO Multimeter survey
Hi Dave,
nearly a month after your encouragement to improve the readability of the dials on my old Avo 7 I have made some progress! I first had a quick test with Tippex Rapid that I happened to have at home, having seen it mentioned on an earlier thread - disaster I'm afraid. Ordered a £1.38 engraver's wax pencil as Plan B and had a session with it on the DC switch tonight, which I'm really chuffed with. Thanks for your helpful advice and encouragement, it is a pleasure to use now that I can easily see what range is set. I'm wondering whether to cover the top surface of the switches when completed to preserve the effect, but don't anticipate too much switch fiddling as it's dedicated to ammeter duties with my lamp-limiter. Cheers Chris |
18th May 2020, 12:41 am | #2526 |
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Re: AVO Multimeter survey
A mixture of Tippex and spirit based varnish.
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18th May 2020, 11:18 am | #2527 |
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Re: AVO Multimeter survey
Yep, looks like you got the mixture just right there! Nice, especially around the screw - and none actually in the slot, well done.
Cheers Chris |
19th May 2020, 11:55 am | #2528 |
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Re: AVO Multimeter survey
On the subject of 15v Batteries, talked about earlier.
I had a look on the usual Auction Site last night and was surprised to see a proliferation of 15v Batteries at much more reasonable prices than they used to be. Ones that jumped out, are this interesting one which can be refilled (allegedly, but I've not tried one as £14.95 is a bit steep for something I can do myself). https://www.ebay.co.uk/itm/AVO-8-MET...IAAOSw5pRcPKV2 Incidently, if you plan to refill with those AG10 Watch Batteries, you would be better buying them from a Jewellers rather than the Pound Shop. They sell/use proper Batteries, not the cheap Tat found in Poundland! This one: https://www.ebay.co.uk/itm/2x-10F20-....c100009.m1982 Although, I think they mean compatable with the B121 not the B154 which is the smaller round 15v Battery. I'm tempted to get a couple of these for testing. There are plenty of others for under £5, which I don't think is an unreasonable price if they last a Year or Two. Ian |
19th May 2020, 1:25 pm | #2529 |
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Re: AVO Multimeter survey
Yesterday on eBay, a couple of fuse for model 4/5 with box was sold at 16 pounds I think.
I have never seen them new in box before. If somebody from here bought them, perhaps can tell us the exact resistance value. |
19th May 2020, 4:33 pm | #2530 |
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Re: AVO Multimeter survey
Hi Aitor,
They were posted a couple of weeks ago for £34 + postage. There were no takers. Difficult to value, but they are very unique. Like you, I have never seen anything like it before, so it just goes to show, anything could be out there waiting to be discovered. Then they disappeared, allegedly because they were lost or broken. Then they re-appeared last week for £14.99 with one very definitely broken. Seller claims they got dropped, but with all honesty, I doubt the Fuse would break like that if you threw it at a brick Wall. I think he probably tried to open one with pliers and got caught out. The Bakelite Tube I think was sometimes glued down from new. I know I would be very tempted to look inside a new unmolested Fuse. or maybe he dropped it, and then stood on it by accident. Either way, it's a bit of a shame. Ian |
19th May 2020, 4:59 pm | #2531 |
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Re: AVO Multimeter survey
Someone got them for £16, maybe someone from here? We'll find out in due course perhaps.
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19th May 2020, 6:29 pm | #2532 |
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Re: AVO Multimeter survey
..I did ask for a resistance measurement across the fuses but for whatever reason it didn't happen.
Dave |
19th May 2020, 7:01 pm | #2533 |
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Re: AVO Multimeter survey
As far as I know, the Resistance of the Avo Fuses is 4 Ohms.
That's what I've always been lead to believe. Although, when I restored my Model 5 a while back, 4.8 Ohms was a better match for the meter. I can't say for sure, but when I was researching these Fuses, I came to the conclusion, that this Value probably wasn't chosen specifically by AWEECO, but was simply the result of the way the Fuse was made and it's design Capacity. I do have an older Meter with what appears to be an unmolested Fuse, so if I get time, I will try to get an actual measurement. Ian |
19th May 2020, 7:53 pm | #2534 |
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Re: AVO Multimeter survey
Thanks
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19th May 2020, 9:51 pm | #2535 |
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Re: AVO Multimeter survey
My Model 4 had a blown fuse which i re-stuffed at 4 ohms. (4.7 ohm and 27 ohm 1/4 watt resistors in parallel.) It does not now act as a fuse- but does allow the meter to work.
I was tempted by the listing for NOS fuses but in reality my meter is so tatty that they would be better going to someone with one in good condition. I do have a couple of the black tubes that go over this general type of fuse (from a Type E)- but had no difficulty removing them- they just pulled off. The reason i ended up removing them was i couldn't fit resistors inside them.. Dave |
20th May 2020, 10:02 am | #2536 |
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Re: AVO Multimeter survey
Ok, I dug the Fuse out this Morning from an early 30's Meter.
The Tube is fixed on, it might pull off, but I don't want to chance it. The hole in the Tube is sealed with Black Wax. I have no idea if this was normal from New, or it indicates that it might have been repaired in the past. It measures 4.12 Ohms according to my Fluke 287 which although not Calibrated, is of reasonable quality and I think can be trusted to be fairly accurate. So, no real surprises there. I can repair old Fuses, provided all the original Parts are still present. That is, the Two small Screws, the Metal End Point and an undamaged Bakelite Substrate. I can't Guarantee the mA Rating but it would be in the order of 120mA. I can normally get the Ohms to within +/- 0.2 Ohm subject to my Fluke. Ian |
4th Jun 2020, 7:05 am | #2537 |
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Re: AVO Multimeter survey
Good morning forum member, i hope everyone is keeping safe.
I have just taken delivery of an Avometer Model 16 that purchased from Canada for a reasonable £20. Which is great when i see a Model 15 just sold on Ebay for £107. The serial number of this instrument is 6951.V.569 (May 1969) Andy |
4th Jun 2020, 4:43 pm | #2538 | |
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Re: AVO Multimeter survey
Quote:
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4th Jun 2020, 4:55 pm | #2539 |
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Re: AVO Multimeter survey
I picked this up in March. It's in a bit of a state, someone's got at it in the past, so I think it'll just be a display item.
No. 074-1063.
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5th Jun 2020, 11:08 pm | #2540 |
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Re: AVO Multimeter survey
I'm not sure if this is the right place for this, but I have an early digital AVO multimeter, it comprises of a digital system mainframe type D.S.109 with a multimeter module type M.M.110.
There is an advert in the May 1969 wireless world here (page 3/A1); https://worldradiohistory.com/UK/Wir...ld-1969-05.pdf It was completely dead when it arrived earlier this year, but re-soldering some bad joints on the +/-12V supply PCB has got it going again in manual mode, it still needs more work to get the internal trigger working (the PCB on the right is not missing, just forgot to put it back when I took the picture), the internal Muirhead reference cell is knackered too. David Last edited by factory; 5th Jun 2020 at 11:27 pm. |