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[Amps] hear hear about the toobs

To: <amps@contesting.com>
Subject: [Amps] hear hear about the toobs
From: 2 at vc.net (2)
Date: Mon Mar 3 14:25:12 2003

>Hello Group !
>
>I have been following the discussion on tubes and I find it very
>interesting.
>I am in no way an expert, but have had my share of 8877's, 3-500Z's.
>
>I can say I did experience a problem with a 8877 in an old Ameritron AL-1500
>I had some years ago, and replaced it with a "Pull" that I purchased
>and was back on the air.  I did not have the skill to check the tube
>to even know if it was bad.  I figured since it had lower then expected
>output, it was time to go.

**  Low  P-out is a symptom of gold-sputtering - wherein gold evaporates 
from the grid and lands on the cathode.  Since the gold poisons cathode 
emission, which lowers I-anode and power output.  
-  I would like to test the tube you pulled and try to find out what's 
what.  I will return tube  via Priority Mail.  If the problem is 
gold-related, it is not difficult to move the gold particles from the  
cathode into the tube base by tapping with a hammer in the vertical 
plane.  This restores emission and the tube can be used as a spare 
provided the base is down.
-  An autopsy photo of a gold sputtered 8877 removed from an AL-1500:
http://WWW.VCNET.COM/measures/8877.gs2.JPEG
The Funderburg (W6IHA) gold sputter test is described on my Web site.  

cheerz, Keith
>
>I am curious is some of the problems in the past that have made company's
>switch to the Russian Tubes, are do they also have similar problems.
>
>I own 2 Alpha-99 Amplifers, and have been gradually accumulating
>4CX800's as spares with the fear that in the future when I need
>some they will be expensive to purchase, or not available.
>
>Would appreciate any comments on my strategy of purchasing
>tubes and putting them in storage.
>
>Thanks,
>Keith, K4KAL
>
>
>
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>


-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
end

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