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[Amps] al80a

To: <>
Subject: [Amps] al80a
From: (2)
Date: Fri, 2 Aug 2002 07:40:13 -0700
I have observed that position makes virtually no difference in 
grid-filament withstanding potential.  //   I performed a hot filament 
sag test with a 3-500Z in horizontal position.  The change in 
filament-grid withstanding potential was c. 500v/month.  In other words, 
it would have taken c. 15-months for the tube to short. 

>From Steve's comment , I went back and ran the same test on the tube in the
>upright, vertical, as it would be in the amp,    position.!!  the result was
>the same. 20-25 ohms as soon as the filament warmed up. !!
>  carl / kz5ca
>----- Original Message -----
>From: "Steve Thompson" <>
>To: "'Amps'" <>
>Sent: Friday, August 02, 2002 1:47 AM
>Subject: Re: [Amps] al80a
>> -----Original Message-----
>> From: carl seyersdahl <>
>> To: 'Amps' <>
To: <>
>> Date: 01 August 2002 23:46
>> Subject: [Amps] al80a
>> > In my FWIW dept. I looked over the entire amp and didn't find anything
>> >conncern. I did find a burned resistor which turned out to be in the
>> >external 12vdc line. , but no burned bandswitch contacts, no evidence of
>> >anything unusual, but still I knew something was wrong.
>> > I tried something interesting , tho, I took the tube out and laid it on
>> the
>> >bench and hooked up the filament with jumpers , connected the ohmeter
>> >between the fil and the grid and when I fired it up, there it was, about
>> >ohms between the two terminals
>> A genuine question on my part, not meant to appear critical of Carl in any
>> way.
>> You described the tube as 'laid' on the bench - if this is on its side
>> rather than standing up, will the filament sag and short when it is
>> up regardless?
>> Steve
>> _______________________________________________
>> Amps mailing list
>Amps mailing list

-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,  

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