KX-1 output problem

[john gindlesberger]

I recently finished my KX-1 and installed the ATU board only to find that my ouput is only about 0.9 watts on 40 and 0.2 on 20.  When I finished the basic KX-1, I put it on an uncalibrated QRP wattmeter and it read about 2 watts, so I thought I was in the ballpark. Now, assuming that my original 2 watt reading is really 0.9, I find that the output is the same both with and without the ATU, so the problem must be in the transmitter and not the ATU.

The KX-1 checked out fine through stages 1 and 2 and the resistance readings for stage 3 were all OK.  I just checked the voltages on Q4, Q5 and Q6 and they are within 10% of the table.  I've checked the continuity for all the toroids and T1, as well and recounting the turns and lead placement.  The output control is fully clockwise and the output is being fed into a 50 ohm dummy load.

All control functions appear to be working correctly and the receiver seems to be normal on all the bands.  

I'm at a loss and could use a healthy does of "elecraft mojo"

Thanks,

John
WA8FNJ
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[Andrew Moore-4]

> I recently finished my KX-1 and installed the ATU board only to find that my ouput is only about 0.9 watts on 40 and 0.2 on 20.

I had a similar problem in my recently completed KX1.  I solved it by
redoing the step in which you null the voltage reading from the trimmer
cap (step says to set your meter at 2-3 VDC max, etc..)

The first time, I attached a 40 meter antenna, which may or may not have
presented a proper 50 ohm load.  The null was at about 78 mV.  The
second time, I used a real 50 ohm dummy load, and got the null down to
zero volts, easily.

Don't forget to set ATU to "CAL" in the menu, rather than "TUNE", before
doing this.  Also don't forget to set it back to "TUNE" when operating
for real :)

Power is back to normal, showing about 2 watts on the 40 meter antenna,
under battery power.  Haven't tried external 12 VDC yet.

Good luck and email me directly if I can be of any more help.

Wayne/Eric and all: this KX1 is simply fantastic.  Nice user interface,
nice quality kit, great sounding CW note (monitored on separate rx),
very very happy op.  Have yet to make my first QSO and looking forward
to it.  Nice job.

--Andrew, NV1B


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[Ken Kirkley-3]

Hey John:
I had a similar problem with my KX1. It ended up being a bad solder
joint on a resistor pack. I cannot remember which one, but if you look
at the schematic
you will be able to locate it. After applying a little heat to the joint
all was OK. Hope this helps in some way.

Ken/NO4D

john gindlesberger wrote:

> I recently finished my KX-1 and installed the ATU board only to find that my ouput is only about 0.9 watts on 40 and 0.2 on 20.  When I finished the basic KX-1, I put it on an uncalibrated QRP wattmeter and it read about 2 watts, so I thought I was in the ballpark. Now, assuming that my original 2 watt reading is really 0.9, I find that the output is the same both with and without the ATU, so the problem must be in the transmitter and not the ATU.
>
> The KX-1 checked out fine through stages 1 and 2 and the resistance readings for stage 3 were all OK.  I just checked the voltages on Q4, Q5 and Q6 and they are within 10% of the table.  I've checked the continuity for all the toroids and T1, as well and recounting the turns and lead placement.  The output control is fully clockwise and the output is being fed into a 50 ohm dummy load.
>
> All control functions appear to be working correctly and the receiver seems to be normal on all the bands.  
>
> I'm at a loss and could use a healthy does of "elecraft mojo"
>
> Thanks,
>
> John
> WA8FNJ
> _______________________________________________
> 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
>

--
73 & God Bless,
Ken/NO4D
http://webpages.charter.net/kgk

Ambassadors For Christ Net +/- 7.280
M-F at 2:00 EST  Sat at 2:30 EST

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