[Elecraft] Dead K3

[Ron D'Eau Claire]

Wow, I'm very sorry to hear that Gentlemen. I trust you've sent messages to
K3support at elecraft.com. 

Dave, your experience with the K3 PCB has been addressed. A shipment of
boards with protrusions on the sides of the PCB in the wrong places was
received from (I understand) a new vendor. Obviously, that was missed when
the parts were received. 

Check Errata B-4 to the KRX3 Assembly manual:

http://www.elecraft.com/manual/KRX3_Errata_Rev_B-4.pdf

It instructs  builders to *carefully* file down the nubs that strike the
sides of the enclosure so the pcb fits properly. 

Also, with reference to VFO B encoder issues, it's been discovered that a
small number of K3s can develop a short between the pins on the back of the
encoder and the main DSP board. The short is caused because, when plugging
the front panel assembly onto the main chassis, the force required to engage
the multipin connector J51 on the DSP board near the encoder can be enough
to flex the board forward to it strikes the pins on the little encoder
board. 

The "fix" is also discussed in the above errata since Elecraft wants
everyone who installs the KRX3 to implement it if it wasn't done during the
initial build. It's in two parts. First, the pins behind the connector on
the back of the little pc board attached to the encoder are trimmed flush to
the board (there's a photo in the errata). That fixes the issue 99.9% of the
time since the main DSP board has to flex much farther to touch the encoder
with the pins trimmed. Secondly, Wayne added a nylon standoff to the design.
It mounts on the main DSP board near that connector and rests against the
front panel board so the DSP board cannot flex toward the encoder. An option
to the standoff is to add a bit of foam tape (like the white, double-sticky
Scotch "mounting" tape used for pictures, etc.) that is a few mm thick over
those pins. Leave the protective covering over one side and stick it onto
the pcb over the trimmed pins. 

If you trim the pins and add a bit of insulation on the back of the encoder
pcb, the standoff should not be needed. Wayne included it to be absolutely
sure the problem was handled. If you'd like to install the nylon standoff,
I'm sure Elecraft will provide the parts if you drop a note to
K3support at elecraft.com.

Ron AC7AC

-----Original Message-----

In a recent message, "Sanger, Joseph" <Joseph.Sanger at nyumc.org> writes
>David, I have the KRX3 sitting in a box ... and your experience 
>confirms my worst fears ... I am really reluctant to tackle the 
>installation ... especially, as you point out, I really don't have any 
>specific need for the subreceiver; just a neurotic need to fully load 
>the box!

Likewise, I only bought the KRX3 so I had a complete system, Joe. In 
hindsight, I wish I hadn't.  The KRX3 did not go together well. There 
were some protrusions on the KRX3 that did not correspond to the holes 
in the metalwork. They caused the metalwork to distort.  A manufacturing 
or design fault I presume.

73 de David G4DMP
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| David M Pratt, Kippax, Leeds, England  |
| K1:1117 KX1:0052 K2:1583 XV144 K3:0186 |
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