First, let's seperate the two pieces and see which is causing the problem.
1. Conduct the same test with just the exciter.
2. Conduct the same test with just the PA. Do this by replacing the
exciter with a 50 ohm load on the PA input and watch plate current while
adjusting plate load and drive through all their ranges. You will be
looking for a spike in plate current. If you see a spike, first tighten
all the amplifier's internal hardware and then go through any neutrilizing
procedures. Let us know how you do.
Dave WA0ZZG
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> Today's Topics:
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> 1. FT-1000D/Alpha 99 problem (Donanpatti@aol.com)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 22 Sep 2007 14:50:14 EDT
> From: Donanpatti@aol.com
> Subject: [Yaesu] FT-1000D/Alpha 99 problem
> To: Yaesu@contesting.com
> Message-ID: <be8.1e346f25.3426bde6@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> Gentlemen: I am driving an Alpha 99 with my FT1000D. Tha antenna is a
> Carolina Windom fed with RG8U through an Ameritron ATR-30. In recent days
> this
> problem has shown up on 80 meters ONLY. As I increase drive power, the
> Alpha
> output increases as it should. But as I approach the 500 watt or higher
> output
> level, turning off the drive(zero drive), the amplifier continues to
> indicate
> high power output as evidenced by the output power LED's and the familiar
> sound
> of load on the Alpha power transformer. And when the drive is cut off,
> there is a significant time lag before the Alpha power output drops to
> zero.
> Station ground hookup has not changed. The ground consists of 1/2 inch
> copper
> pipe directly through the wall to a 10 foot copper ground
> All equipment connects to the pipe via battery clips. All comments will be
> appreciated. 73 Don W8WOJ
>
>
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> End of Yaesu Digest, Vol 57, Issue 13
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