[Elecraft] RE K2 AGC off problem

[Robert Allbright]

> From: Robert Allbright <rob at robg3rce.plus.com>
> Date: 23 March 2006 11:33:05 GMT
> To: elecraft at mailman.qth.net
> Subject: K2 AGC off problem
>
> Hello Werner
>
> I replaced X1 and all is now well with K2 5219, just need to build  
> the KPA100w amp sometime.
>
> see the note below from Ken K3IU (thanks again Ken)
>
> 73
> Robert G3RCE
>
---------------------------
>
> Message: 8
> Date: Thu, 23 Mar 2006 09:15:47 +0100
> From: "Dr. Werner Furlan" <furlan at gmx.net>
> Subject: [Elecraft] K2 AGC off problem
> To: elecraft at mailman.qth.net
> Message-ID: <44226743.25716.1289F7C at furlan.gmx.net>
> Content-Type: text/plain; charset=US-ASCII
>
> hi all,
>
> I should have posted this before...
> I found a related message when searching the archive. The reply was:
>
> ------------------
> Sounds exactly like the problem I had with 5196. The problem was  
> fixed by
> replacing X1 on the Control Board. You will probably find that  
> CtrlBd-U2-1
> goes to about 6 volts when you turn the AGC OFF virtually shitting  
> down the
> IF amplifier. I encourage you to communicate with Gary
> (support at elecraft.com) regarding this problem. Yesterday, someone
> reported a
> similar problem with a close serial number(s/n5219).
> ----------------------
>
> My serial # is 5203, so maybe I am also affected by this failure?
>
> 73! de Werner OE9FWV
>
> -- 
> EYEDROPPER:  A clumsy ophthalmologist
>
>>> Hello Robert:
>>>
>>> I recently had a problem with the AGC on a K2(5196) that I was  
>>> assembling.
>>> In my case, what was happening was when I turned the AGC OFF (PRE/ 
>>> ATT + AGC)
>>> the AGC voltage back to the IF amp was going very high and basically
>>> shutting down the IF amp. This also resulted in the S-meter  
>>> indication going
>>> high. You can easily check this by measuring the DC voltage on U2 
>>> (on Control
>>> Board) pin 1.  If this voltage shoots up (In my case it went to  
>>> about 6
>>> volts) when you turn the AGC OFF, then that is what is happening.  
>>> After
>>> consulting with Gary Surrency (support at elecraft.com), I replaced  
>>> a bunch of
>>> components, but of course it was the last component that was  
>>> changed that
>>> solved the problem... X1 was bad. If this is what you find, then  
>>> I suggest
>>> that you email Gary, let him know what you find. Of course,  
>>> always be sure
>>> that all components of the right values are in the right place  
>>> and RE-check
>>> the soldering.
>>>
>>> Of course, this may not be your problem at all, but it sounded so  
>>> similar to
>>> mine, I thought I'd pass along my experience.
>>>
>>> Good luck & 73,
>>>
>>> Ken Wagner K3IU
>>>