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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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12th Feb 2019, 7:10 pm | #1 |
Pentode
Join Date: Dec 2018
Location: County Meath, Ireland
Posts: 242
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Avometer Movement balance ?
Folks,
I recall seeing a video on the internet somewhere which showed how to re-balance the movement. But I can't find it now!!! It showed how to add nail varnish to counterweight the movement so there is a good balance between vertical and horizontal meter positions. Does anyone have it bookmarked by any chance? Or can give me some tips on the procedure? Thanks Ray
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Regards Ray |
12th Feb 2019, 8:21 pm | #2 |
Octode
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,604
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Re: Avometer Movement balance ?
It's always interested me, though I'm too chicken to do any such thing to a movement!
If it zeros fine in the horizontal position, I'm not worried what it does vertically.
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Avometer, vintage Fluke and Marconi collector. Also interested in vintage Yaesu and KW. |
12th Feb 2019, 8:30 pm | #3 |
Pentode
Join Date: Dec 2018
Location: County Meath, Ireland
Posts: 242
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Re: Avometer Movement balance ?
I found this guide...
http://www.rfcafe.com/references/qst...b-1943-qst.htm It's as simple as A,B,C (see paragraph half way down the article) It requires the meter to be removed from the Avo... perhaps next time!
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Regards Ray |
12th Feb 2019, 8:59 pm | #4 |
Pentode
Join Date: May 2018
Location: Cologne, Germany
Posts: 104
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Re: Avometer Movement balance ?
I found this guy who is balancing a meter. But the article you posted is pretty good.
https://www.youtube.com/watch?v=CxSsO3zo2hs I would like to see a tutorial on how to adjust the jewel screws, text or video Last edited by sven_swe; 12th Feb 2019 at 9:10 pm. |
12th Feb 2019, 10:10 pm | #5 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,935
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Re: Avometer Movement balance ?
I've used the method described in the RF Cafe link on an Avo VCM meter. Requires a steady hand and a fine paint brush. Not sure that nail varnish is a good choice; you may overdose it and need to remove some.
I used an obscure chemical called Salol, which is like a wax which melts at ~40'C. I had been told to use Salol in a previous life to bond piezo elements, and of course, it was subsequently easy to de-bond them, or on a meter, remove a dab using something like a "warmed" jeweller's screwdriver. B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
12th Feb 2019, 10:45 pm | #6 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,107
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Re: Avometer Movement balance ?
When i researched this originally, i think i searched under 'balancing a d'arsonval movement' which came up with at least one good (quite old) source.
Having Zeroed the needle you proceed to check and rectify Tail, then Side. I use car paint personally. There is little risk of overdoing it since it loses some solvent weight in the first couple of minutes after application. If a tail weight in (eg an Avo) has corroded away paint may not be heavy enough, i have resorted to embedding a tiny lump of lead/tin or copper in the paint on a couple of occasions. Nail varnish dries too quickly for my liking- there's more wiggle room with paint. If your Avo only shows 2% under or over 'Zero' on carrying out the recommended orientation checks, it is not worth doing anything about it. Dave |
12th Feb 2019, 10:50 pm | #7 |
Guest
Posts: n/a
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Re: Avometer Movement balance ?
just to warn if someone use cello tape to fix the needle (or the pointer), that many old scales suffer or curling paint that comes off very easy.
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13th Feb 2019, 7:21 pm | #8 |
Pentode
Join Date: Dec 2018
Location: County Meath, Ireland
Posts: 242
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Re: Avometer Movement balance ?
Thanks guys, good information there.
I won't try it just yet, my meter is nicely closed up and working well. It's probably within 2% of where it needs to be on the vertical but it's almost perfect on the horizontal. But perhaps next time i have reason to open her up.
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Regards Ray |