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Re: [Amps] AL-1200 Grid Current - negative?

To: AMPS <amps@contesting.com>
Subject: Re: [Amps] AL-1200 Grid Current - negative?
From: Dana Roode <K6NR@ARRL.net>
Date: Sun, 09 Nov 2003 11:36:49 -0800
List-post: <mailto:amps@contesting.com>
Amps folks -

Ok, I removed the tube and the meter still went negative. I checked the filament connections with the tube out, nothing is shorted to ground.

I was suspect of the metering circuit itself. The left multi-function meter measured 300 ohms across the terminals, the right grid meter measured 15k. The parts list indicates both meters are 300 ohm 1ma.

I took the grid meter apart, it has a component (a precision resister, I assume) in series with each internal meter movement lead. One measured 100 ohms, the other about 15k.

I am pretty clueless about this, and Im at a loss as to why a 100ohm resister would become 15k, but perhaps this is my problem.

Dana


Dana Roode wrote:
What does it mean when you power up an AL-1200 and the grid current meter pins negative (no drive power supplied)?

Dana

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