[Elecraft] KX-1 has been born, TWICE

Don Wilhelm w3fpr at embarqmail.com
Sun Apr 5 18:49:39 EDT 2009


Bob and all,

Bob is correct, the free green lead of L2 must not make contact with the 
L2 lead 4 (red) solder pad or wire.
The manual tells the builder to strip the green wire leaving 1/8 inch 
(3mm) of insulation beyond the point where the wire leaves the core.  
First step, do that, it may be adequate with no further work, but read on.

After L2 is mounted on the board, next step is to form the green wire so 
it passes behind the LPF board at a location above the solder pad for L2 
lead #4.

Then, take a look at it, and if you find that the green wire lead has 
any chance of contacting the L2 lead 4 solder pad at the back of the 
board once it is mounted, use a 3/16 inch (4.5mm) piece of insulated 
tubing (cut from the same wire you used to insulate the + lead of the 
electrolytic capacitor) on this green lead.
Yes, the thickness of the insulation will move the LPF board a bit away 
from KX1 board J7. but push the board as tightly against J7 as possible 
and all should be fine.

As another hint, the Low Pass Filter board should be positioned so the 
outer edges of L1 and L2 are aligned right at the edge of the KX1 board 
- you can 'eyeball' this condition, but do it before soldering the leads 
of the LPF board to the KX1 board.  Test fit the KXAT1 before putting 
the KX1 board in the enclosure.  If there is interference, you can 
usually move the KXAT1 T1 core over a bit to make room for the KXB3080 
LPF board - the clearances are tight, but they do work out.

Above all, work carefully building this KXB3080 LPF board, and be doubly 
certain that the toroid leads are well stripped - flush trim the relay 
leads so they do not injure the enamel on the toroids.  Problems with 
this board is the most frequent cause of failure with the KXB3080 
installation - again work carefully, strip the toroid leads well, and do 
not use excess solder, and success can come to you too.

73,
Don W3FPR


B.G. wrote:
>
> My only nit-pick refers to the (routing) of the green toroid wire L2-1 from the LPF1 module to the KX-1 BOARD.  The errata sheet gives the 100% correct procedure, but practicality told me it won't work.  After a quick call to Scott & a call from Don W.,  a procedure was suggested which I recommend for all builders.  Maybe Don can post on the reflector.  It involves using a 3/16" piece of the Green insulation.  WORKS PERFECTLY.  Thanks guys.
>   
>


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