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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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17th Aug 2017, 6:19 pm | #1 |
Octode
Join Date: Jun 2005
Location: Sheffield, South Yorkshire, UK.
Posts: 1,227
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Testing rectifier with AVO MK1
I have a suspect 6X5GT from a Toaster radio. It only reads 180 V on the cathode target 260V. I tried to test it on AVO Mk1 tester yesterday but the instructions are unclear. I couldn't get a reading on either diode. Can anyone advise me?
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18th Aug 2017, 11:34 am | #2 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Testing rectifier with AVO MK1
None of the testers do a particularly good job of testing rectifiers. The AVO 2-panel meter only does an emissions test.
If the set is taking the correct current and the dropper resistance is correct then you can assume the valve is low. |
20th Aug 2017, 10:23 pm | #3 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
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Re: Testing rectifier with AVO MK1
I can let you have a good 6X5GT for a couple of quid plus postage - drop me a PM.
The Avo twin-panel tester also measures gm, but not on rectifiers of course! It's a while since I used one but I remember that it tested rectifiers perfectly well.
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Phil Optimist [n]: One who is not in possession of the full facts |
21st Aug 2017, 8:00 am | #4 |
Nonode
Join Date: Mar 2008
Location: Aberdeen, UK.
Posts: 2,853
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Re: Testing rectifier with AVO MK1
Just wondering - are we talking about an AVO VCM MK1, or a Twin-Panel Tester ? They are very different.
Regards, David |
21st Aug 2017, 1:45 pm | #5 |
Octode
Join Date: Jun 2005
Location: Sheffield, South Yorkshire, UK.
Posts: 1,227
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Re: Testing rectifier with AVO MK1
I was talking about a 1948 twin panel tester.
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22nd Aug 2017, 2:28 pm | #6 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
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Re: Testing rectifier with AVO MK1
Well, I amongst others was under the misapprehension that the twin-panel and the MkI were one and the same thing! Is it correct that the "AVO Valve Tester" referred to in the Avo valve data books is the twin-panel tester? The control settings would seem to confirm that.
Slightly OT I know, but if someone could post a picture of a VCM Mk I it would clarify the situation. Pete, your valve's in the post!
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Phil Optimist [n]: One who is not in possession of the full facts |
22nd Aug 2017, 3:23 pm | #7 |
Nonode
Join Date: Mar 2008
Location: Aberdeen, UK.
Posts: 2,853
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Re: Testing rectifier with AVO MK1
Hi Phil & Pete,
The designations of AVO's range has raised queries a number of times over the years. The photographs at the front of the AVO Valve Data Manual clearly list the centre picture as "Valve Characteristic Meter. Mk's 1 & 2" i/e. VCM Mk1 & VCM Mk2. The bottom r/h picture is just called "Avo Valve Tester". Known colloquially as "The Two Panel" amongst the vintage fraternity. Likewise, in the valve data pages - r/h side - there is a separate tabulation of settings called "DATA FOR AVO VALVE TESTER". Very confusing I know. Some folk do refer to the Two Panel as Valve Tester No1. Regards, David |
22nd Aug 2017, 6:11 pm | #8 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
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Re: Testing rectifier with AVO MK1
David, it probably depends on which edition of the AVO Valve Data Book you're looking at! Mine only shows a picture of the VCM Mk III, probably the current model at the time the book was published.
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Phil Optimist [n]: One who is not in possession of the full facts |
22nd Aug 2017, 6:56 pm | #9 |
Tetrode
Join Date: Jan 2016
Location: Jarrow, Tyne and Wear, UK.
Posts: 81
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Re: Testing rectifier with AVO MK1
Borrowed from the net, a picture of an avo vcm mk1 and a mk 11 together
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22nd Aug 2017, 7:00 pm | #10 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
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Re: Testing rectifier with AVO MK1
Thanks Neil
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Phil Optimist [n]: One who is not in possession of the full facts |