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[AMPS] Need help with Ameritron AL-80A

To: <amps@contesting.com>
Subject: [AMPS] Need help with Ameritron AL-80A
From: mjorba@ingelan.com (Marcel Jorba)
Date: Thu, 12 Apr 2001 21:16:13 +0200
Rich,

Thanks for your help.

1.- Where the 100 ohm supressor resistor should be? I can't locate it.
2.- My english is limited. What do you mean with "hot-pot the tube"
3.- What a DMM means?

BTW: Is the a retrofit-kit for the al-80? Might it help  to avoid future
problems like this

Thanks again,

Marcel, EA3IN




>>> measures <2@vc.net> 04/12 8:25 p.m. >>>

>
>Hi !!
>
>I have been using my AL-80A for years without trouble. Sudenly, during
>last WPX, the amplifier stoped because thes fuse blowed. After restoring
>
>the fuse I observed that the 3-500Z showed blue color (gas?) at top, so
>I replaced the tube as well. 

?  A blue glow On the glass is ok - A blue glow between the anode and the 
(grounded) grid indicates a bad seal.  .  

>No other symptom and all components seemed
>to be intact
>
>When starting with the new tube i observed the grid current and ip
>current indicators going full scale when transmiting with very low
>power. The wattmeter shows normal output power.
>
>After looking at the reflector I replaced the 1n4007 diode because it
>solved the problem when experiencing similar situations. 

?  This suggests that there was some kind of temporary glitch.  

>After this ip
>current indicator goes full
>scale even if I don't transmit (Grid meter indicates zero). If I apply
>normal drive the grid current and ip current indicators go full scale
>again. The wattmeter shows normal output power.
>
>Any idea?
>
?  I would:
1.   test the accuracy of the meters with a DMM.  
2.  high-pot the tube.  
3.  measure the actual resistance of the 100-ohm suppressor resistor.  

cheers, Marcel
>
>
>
>
>
>
>--
>FAQ on WWW:               http://www.contesting.com/FAQ/amps 
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>Problems:                 owner-amps@contesting.com 
>
>


-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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