[Elecraft] KX1 modules question

[Ron D'Eau Claire]

Tim, you'll install connectors on the RF board that the ATU plugs into when
it's built. To operate the KX1 without the ATU, you install a jumper between
two pins on one of the sockets to complete the RF path. That's covered in
the assembly procedure in the manual. 

I recommend building the basic KX1 and then adding the ATU and 30 meter
modules one at a time. That makes checkout and troubleshooting much easier. 

Some people have had trouble with shorting the power transistor to the case
while others do not. My KX1 was opened up and the case removed dozens of
times while writing the assembly instructions. I never got a short. Others
couldn't assemble it once without problems. 

Corresponding with several of those who did have an issue, the consistent
reason seems to be that sometimes the hole in the case for the flat-head
screw or the bevel on the bottom of the flat-head screw allows the conical
bottom section of the head to 'reach' through the insulator and touch the
tab on the transistor when the assembly is tightened. A couple of builders
confirmed this pretty well by substituting a pan head screw and finding that
the short went away. 

I've not seen reports recently, so I don't know if a "fix" has been
implemented in the form of a different screw or if the initial issues were
just with a certain batch of covers with holes slightly too large. If you
have any trouble in this area, I suggest trying the same "fix" and see if
the short goes away when you substitute a pan-head screw. If it does,
contact Gary (service at elecraft.com) for a permanent fix.

If it goes together right the fist time without any shorts, you should not
have any troubles after that. You can open it up easily and add the 30 meter
module when you're ready. If you do encounter a short on re-assembling the
unit, make sure the insulating thermal pad is in place and that no bits of
metal are sticking through it. Some builders have captured on the pad a tiny
bit of a lead that was clipped off during assembly. When the screw is
tightened, it is forced through the pad to cause a short between the metal
tab on the transistor and the case. Keep the work area clean <G>.  

Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Tim Hodges
Sent: Tuesday, October 19, 2004 10:46 AM
To: elecraft at mailman.qth.net
Subject: [Elecraft] KX1 modules question


Greetings;

I am nearly complete with construction of the base KX1. Great kit, my 
only possible quibble is the whole Q6 issue. But,I now am going to be 
building the 30M and ATU module. I want to minimize how many times I 
remove the KX1 main board from the case. Is there any logical order 
between the 30M module and the ATU as far as which one I should do next?

72 de Tim KD7JZ

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