[Elecraft] New KPA100 no receive on SO239

[Don Wilhelm]

Cathy,

You must have the ribbon cable connected.  With that connection and the 
power turned on the base K2 (no power to the KPA100), you should have 
continuity between the center of the KPA100 SO-239 jack and the center 
conductor of the KPA100 board RF IN coax.
Yes, the KPA100 Low Pass Filter is in the path.  The base K2 12CTRL line 
powers the relays as well as the MCU and other control circuits in the 
KPA100.
The relays in the KAP100 are not latching type.
If you do not have continuity as described above, check the soldering.  
The KPA100 has a large copper ground plane area.  If you did not use a 
soldering temperature of the recommended 800 degF, you may have 
inadequately heated solder connections - reflow the soldering until you 
see the solder flow out fully onto the solder pad and the component lead.

Do you have the center conductor of the coax header which plugs into the 
base K2 correct?  The shield is closer to the K2 side panel than the 
center conductor.
Check the insertion of the crimp pins of the J1 header to make sure they 
are correct.  Looking into the rectangular holes in the header, you 
should see the locking tabs latched behind the plastic, and you should 
be able to wiggle the crimp pins slightly by pushing/pulling on the coax 
wires.

73,
Don W3FPR

On 1/2/2016 5:10 PM, Catherine James wrote:
> I have largely completed building my KPA100, and reached the point in testing where the speaker works if connected to the base K2 with the signal coming in through the BNC antenna port.
>
> However, I have been unable to hear anything when the antenna is connected to the KPA100's SO239 antenna port.  On 40m, I had a strong signal coming in on a different receiver, but switching the same antenna to the K2/100 produced silence.  (Because of lack of signals on other bands lately, I cannot do a good receive test on other bands.  The K2 receiver is too quiet to use normal band noise for a good test!  I may have to create my own QRP signal from a different transmitter into a dummy load to have a signal to listen for.)
>
> I have traced DC continuity from the RF Aux pin on the KPA100 board to TP2 and TP3. I have also traced DC continuity from the center pin of the SO239 to T4-6, T4-5, and C1.  I also appear to have DC continuity between L4, L5, and L6.
>
> Are K5 and K6 latching relays?  Should I have DC continuity from RF Aux RFIN all the way to J2, going through the low-pass filter of the band most recently selected?  Or do K5 and K6 open on all bands when power is off?
>
> What should I check next?
>
> 73,
> Cathy
> N5WVR
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