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Re: [Amps] TL-922 voltage / bias

To: tomp@prohigh.com, km1h@jeremy.mv.com
Subject: Re: [Amps] TL-922 voltage / bias
From: TexasRF@aol.com
Date: Fri, 12 Feb 2010 10:40:13 EST
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Tom, you mentioned having a stiff 240vac line. How stiff? What does it  
measure when the amplifier is maxed out in the SSB position at the 1000w  level?
 
73,
Gerald K5GW
 
 
 
In a message dated 2/12/2010 9:35:03 A.M. Central Standard Time,  
tomp@prohigh.com writes:

There  are 2 tubes in the TL-922.  The grids are DIRECTLY connected  to
ground, I removed the caps and chokes and also put in a second ground  wire
from VC1.  This eliminated some arcing/parasitics I was  having.  The tubes
are original Eimac 3-500Z not 3-500ZG.  The  color on the plates is fine, no
color at idle and red/orange at full  drive.  I do get about 600-700W out on
CW, but only about 1000 key  down on SSB on 20M.  80M is somewhat higher

Tom - AB3FL

On  Fri, Feb 12, 2010 at 10:30 AM, Carl <km1h@jeremy.mv.com>  wrote:

> That idle current is fine for 1 tube and the voltage drop  is excessive.
> Start by measuring the grid chokes for an open or  looking for color on 
both
> plates.
>
> Carl
>  KM1H
>
>
> ----- Original Message ----- From: "Tom Prohigh"  <tomp@prohigh.com>
> To: <amps@contesting.com>
> Sent:  Friday, February 12, 2010 9:47 AM
>
> Subject: [Amps] TL-922  voltage / bias
>
>
>   I have recently aquired a  TL-922.  It is on a stiff 240V line which
>>  actually
>> measures 245V.  No load voltage on CW is 2200 and on  SSB is 3100.  Under
>> full load the CW drops to 1900V @ 600ma  and the SSB drops to 2400V @
>> 800ma.
>> Is there really  suppose to be this much drop?  It has the original 200uf
>> caps  in it and I was thinking about replacing them with 560uf units.   
Also
>> the grid bias on CW is 60ma and on SSB 120ma which seems a  little low.
>>
>>
>> thanks
>>
>>  Tom - AB3FL
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>>
>
>
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