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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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16th Dec 2011, 8:37 pm | #1 |
Triode
Join Date: Jul 2011
Location: Cambridgeshire
Posts: 43
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AVO glass replacement
Hi,
I've bought an AVO 8 with a cracked glass (otherwise seems to be good), and another with a good glass (otherwise seems to be not good - the needle drifts about when the meter is inclined). Before I take them to pieces (to fit the good glass in the otherwise good meter), and possibly do some harm, is there anything I should know? I must admit to spending a very short amount of time seeing if the case would seperate on one of them, but it didn't, so I didn't try any more incase there is something I didn't know about. Thanks.....Mike |
16th Dec 2011, 10:21 pm | #2 |
Nonode
Join Date: Jan 2010
Location: Edinburgh, UK.
Posts: 2,008
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Re: AVO glass replacement
There 5 screws round the rim of the back case. 1 may have pitch over it. Remove these and the 2 parts will separate.
PM me your email address and I will send you a copy of the service manual. Al
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I won't tell you how I discovered that. |
17th Dec 2011, 9:06 pm | #3 |
Nonode
Join Date: Mar 2008
Location: Virginia Water, Surrey, UK.
Posts: 2,877
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Re: AVO glass replacement
A few obvious points
Good luck and well done to be getting an Avo back on its noble feet. Jeremy
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Jeremy, G8MLK, BVWTVM Friend, VMARS, BVWS Secretary. www.pamphonic.co.uk www.bttt.org.uk |
18th Dec 2011, 12:31 pm | #4 |
Octode
Join Date: Oct 2007
Location: Exeter, Devon, UK.
Posts: 1,554
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Re: AVO glass replacement
Meter glass. You are quite right to stick to glass. Plastic / perspex collects static, and the needle will stick. Avo are very strong on this in their service notes. Have you considered getting a fresh piece. When I have had to replace meter glass, often with a small cut out for the zero screw, I have found my local glass merchant very helpful. They seemed to enjoy the challenge of curves and notches. And they would happily use 1/16 thick glass with no arguement. Have you tried replacing an old pane of glass - must be 4mm for safety reasons. So I always specify horticultural or for a picture. Bill m0wpn
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18th Dec 2011, 2:05 pm | #5 |
Octode
Join Date: Nov 2005
Location: Surrey, UK.
Posts: 1,870
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Re: AVO glass replacement
Remember that if you remove the movement from the front panel (all due precautions needed) you will still need to set the cutout trip point. This is done by rotating the cutout base plate.
It's not a difficult job but I hate doing it as finding the trip overload point seems to be rather brutal to the meter. I usually set them to trip earlier rather than later to avoid hammering the movement. The only consequence of this in use appears to be the occasional random trip on mechanical shock with a slight reluctance to reset. This is not usually a problem in actual use. Leon. |