>
>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
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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