[Elecraft] K2/100 CAL acting up?

[Casey Bahr]

Do NOT have power control with KPA100, have power control with base K2

Diode voltage drop values using my DMM's diode test function (fwd/rev bias):
D16 .246/.278
D17 .151/.160

with diodes in place.

73,

Casey

On Thu, November 9, 2017 6:50 pm, Don Wilhelm wrote:
> In normal operation you cannot use TUNE/DISPLAY to monitor the power
> output and SWR.
>
> Yes, those values are the power and SWR as measured by the KPA100
> wattmeter.
>
> Given your readings along with the HI CUR messages, I believe there is a
> problem with the KPA100 wattmeter. To test that theory, connect an external
> wattmeter to the KPA100 and a dummy load. Set the power to 50 watts (or 5
> watts if powering only the base K2). Then do a TUNE.  Do you have power
> control?  Or does the power output go to maximum (greater than 15 watts if
> only the base K2 is powered, or greater than 120 watts if the KPA100 is
> powered.
>
> If there is no proper power control, then the wattmeter in the KPA100 is
> damaged.  The most common cause is that KPA100 diodes D16 and D17 have been
> damaged.  If changing them does not cure the problem, then there are other
> components that could be the problem.
>
> Let us know what the results of your testing may be and we can help
> further.
>
> 73,
> Don W3FPR
>
>
> On 11/9/2017 6:08 PM, TI2/NA7U wrote:
>
>> I see that the small aux board must be removed as there is a "null" pin
>> in the plug and cable, so went ahead and did that and hooked up the
>> KPA100 with
>> its RF out to the meter to the dummy load.
>>
>> When I hold TUNE/DISPLAY, I get a display that looks like <x.y> <x.y -
>> z> with values when power is turned all the way down: 0.1 1.2-1 and all
>> the way up 4 2.1-1 Is that pwr and swr?
>>
>> If I key down the display reverts to frequency immediately, so seems I
>> can't use TUNE/DISPLAY to monitor the power setting or key down output.
>>
>> As I turn the power up or down I get HiCur almost constantly until I
>> let go of the power button. The behavior of the knob is not smooth,
>> jumps a few to several watts sometimes. Not sure if that's a dirty pot
>> or a control board problem.
>