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Re: [Amps] Soft 8877???

To: "Steve Thompson" <g8gsq@qsl.net>, "AMPS" <amps@contesting.com>
Subject: Re: [Amps] Soft 8877???
From: R.Measures <r@somis.org>
Date: Tue, 7 Oct 2003 09:13:14 -0700
List-post: <mailto:amps@contesting.com>

>On Tuesday 07 October 2003 01:55, Paul Ash wrote:
>> Hello All,
>>
>> A quick newbie question.
>> I recently picked up an old Henry 3K X
>> that had sat unused for the last 17 years.
>> This is the version with the 8877.
>> This is my first 8877 based amp and I'm seeing
>> some odd behavior:
>>
>> Max power out 700W. (from what I understand
>> I should be getting 3X that.)
>> Virtually no grid current.
>> Plate voltage looks ok, 4000V in SSB 3000V in CW mode. However, the output
>> does not change from one plate voltage to another. Just seems to hover
>> around 500-700W. I have tried driving it to 900mA on the plate
>> and 400mA on the plate, observed some difference but
>> not much, maybe 25% difference.
>>
>> Any ideas? At first I thought it might be the tuning circuits but I'm not
>> sure. Or, is it the tube? Seems to me that if I can pull 900mA through the
>> plate then the tube may not be bad...
>Could it be that the loading is much too heavy, so the plate sees too low a 
>resistance?
>
***   If either the Tune or Load control is at an end stop when P-out 
peaks, there is usually a bandswitch problem.

-  R.L. Measures/Rich..., AG6K, 805.386.3734, www.somis.org 

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