K3 "No ATU" and 12w max

[CX7TT]

This morning I turned on K3 #250 and got a ERR AT3 msg which was strange
as when I shut down the radio yesterday, everything was fine. I rarely
use the ATU as I have a Steppir beam and inverted L which I run thru an
external tuner.
I started troubleshooting and went thru the following sequences:
After seeing the ERR AT3, I check the config, it was in BYP.
ATU Tune- No ATU
Config-ATU to auto
ATU Tune-No ATU
Power-OFF/ON
No msg this time
ATU tune- ERR LPF
ATU tune-ERR IO3
ATU tune-ERR IF1
ATU tune-ERR xv3
ATU tune-AT3
ATU tune-ERR PA1
ATU tine- ERR BP3

Xmit/Tune- 12 w max (KPA100 installed)
SWR shows 1.8 on K3 display, LP Pan shows 10.6w and SWR of 1.15 (on
exact Steppir freq of 14.050)
Same with ATU in BYP or Auto
KPA3 in nor

Any ideas/suggestions
73
Tom
CX7TT
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[w7aqk]

Tom and All,

Sounds familiar!  Your K3 serial number is low enough to be one that may be
affected (mine is #96) by a problem that is fairly easily corrected.
There's a cap that needs to be removed (if it hasn't been already, and
another small cap that needs to be added.  I see you have copied Gary
Surrency, and he will undoubtedly supply you with the complete details (if I
am right about the issue).

If this happens again in the meantime, try this--disconnect the K3 from all
power, and let it sit for a while.  It may have to remain disconnected for a
while.  Chances are that this will temporarily restore your ATU.  Sometimes
I had to wait 30 minutes to an hour before this worked.  After I made the
mod, the problem has not returned, so I think it is solved.

Since it is the weekend, you might not hear from Gary until Monday.  I can
send you the info he sent me, but I'm assuming it's the same problem.  The
cap that needs to be removed is C19, and the cap that needs to be added is
an SMT cap (300 pf I think).  You just tack it across two pins on an IC.

Let me know if you need the info.

Dave W7AQK


----- Original Message -----
From: <[hidden email]>
To: <[hidden email]>; "Gary Surrency" <[hidden email]>
Sent: Saturday, February 06, 2010 3:17 AM
Subject: [Elecraft] K3 "No ATU" and 12w max

> This morning I turned on K3 #250 and got a ERR AT3 msg which was strange
> as when I shut down the radio yesterday, everything was fine. I rarely
> use the ATU as I have a Steppir beam and inverted L which I run thru an
> external tuner.
> I started troubleshooting and went thru the following sequences:
> After seeing the ERR AT3, I check the config, it was in BYP.
> ATU Tune- No ATU
> Config-ATU to auto
> ATU Tune-No ATU
> Power-OFF/ON
> No msg this time
> ATU tune- ERR LPF
> ATU tune-ERR IO3
> ATU tune-ERR IF1
> ATU tune-ERR xv3
> ATU tune-AT3
> ATU tune-ERR PA1
> ATU tine- ERR BP3
>
> Xmit/Tune- 12 w max (KPA100 installed)
> SWR shows 1.8 on K3 display, LP Pan shows 10.6w and SWR of 1.15 (on
> exact Steppir freq of 14.050)
> Same with ATU in BYP or Auto
> KPA3 in nor
>
> Any ideas/suggestions
> 73
> Tom
> CX7TT
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html 

______________________________________________________________
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Please help support this email list: http://www.qsl.net/donate.html