K3 Audio Upgrade Mod

[Roy Morris-6]

If it only takes 15 minutes to install the RFC 47 via the long method, then I suspect this is a modification in a K3 without the KRX3.  I used the short method because I did not want to have to remove the KRX3 and the TMP cables.  I find the TMP cable connections to the KRX3 are difficult to deal with, especially J92.  The short method can be neatly done, and the RFC 47 pigtails are stretched out allowing the choke to lie flat against the PCB.  A good sharp Exacto knife makes a small incision in the PCB that is unobtrusive.  Removing the KRX3 is not recommended because you could see ERR BP3 then ERR IF2 when SUB is tapped.  These error messages mean you have to remove the KRX3 lid, de-install KNB3, tap SUB in CONFIG: KNB3 menu, turn power off and re-install KNB3 to clear the KRX3.

I agree that you don't want to have any caffene in your system when working with the R19 and R20 SMT piggyback resistors.  I used a toothpick to hold them in place.  I used a small chisle point on the soldering iron.  Do the soldering in the middle of the table.  These little resistors can jump, and you want them to land on the table and not on the carpeted floor.

I really believe the new RFC 47 has deminished the audio harshness with NR on.

Roy Morris  W4WFB

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[gm3sek]

Roy Morris wrote:
>If it only takes 15 minutes to install the RFC 47 via the long method,
>then I suspect this is a modification in a K3 without the KRX3.  I used
>the short method because I did not want to have to remove the KRX3 and
>the TMP cables. 

Another variation is to remove the top cover as well as the bottom
cover, and push the old RFC out from below.

With the two covers removed and the rig upside-down on the bench, first
use solder wick to remove any surplus solder, then heat each pad and
push the lead of the RFC through the hole using a sharp probe. The RFC
drops out onto the bench. This method works equally well with the KRX3
in place, because the RFC falls clear of the KRX3 housing.

The new RFC can then be soldered underneath the board without needing to
cut any tracks.


--

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com