[Elecraft] K2 KPA100 SWR Bridge Readings Way Too High

[Dick Lamb]

Don,

I set both R26 and R27 to 43K Ohms, applied power directly to the base unit
(no power to KPA100), and set power know to call for 10 W.  In TUNE mode
the SWR reads about 9.9:1 regardless of C1 setting.  I think the C1 setting
has no effect.  I measure the power out at about 15 W, and the K2 says it's
putting out about 5 W.  Voltage at U5 Pin 3 is about -1.040 V.

The actual power out stays high when I adjust the power knob (exiting TUNE
mode between attempts), but it starts falling off rapidly when I call for
less than 1 W.  At calling for 0.1 W (full CCW on the power knob), U5 Pin 3
is about 70 mV, SWR reads 4:1, the K2 display says 0.1W output. (I'd guess
real output at that point is around 1.0 W--hard to interpolate that low on
my Heathkit HM-2140 power/SWR meter.

I've checked and tried a couple different dummy loads and jumper sets, and
I confirmed D16 and D17 are mounted in the right direction.

Dick, K0KK