[Amps] TL-922 voltage / bias

Cecil Acuff chacuff at cableone.net
Fri Feb 12 07:50:18 PST 2010


As I have always heard, this is not a legal limit amp so 700 watts out on CW 
and 1000 on SSB would be about right I would think.

Are they consistently doing more than that?  The few I've had through the 
shop here may have been a bit higher but not by much.  All fully unmodified 
of course.

Cecil
K5DL
----- Original Message ----- 
From: "Tom Prohigh" <tomp at prohigh.com>
To: "Carl" <km1h at jeremy.mv.com>
Cc: <amps at contesting.com>
Sent: Friday, February 12, 2010 9:34 AM
Subject: Re: [Amps] TL-922 voltage / bias


> 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 at 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 at prohigh.com>
>> To: <amps at 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
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>>
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