[Elecraft] KPA-100 low power problem on 17m..10m

[recarter at adelphia.net]

I just finished the KPA100 for my K2 this week.  The K2 and associated accessories were purchased within the last month.  Without the KPA100, I get 10W or more on each band.  Most bands provide about 15W, but 10M barely makes the 10W rated output with about 10.5W.  I think the K2 is just fine.

I added the KPA100 board this week.  I get full power on 20m and below, but I only get about 70W on 17M and above.  If I select 50W with the power control, I get 50W out.  As I increase power, the amplifier tops out.  I'm connected to a good dummy load.  The SWR is 1:1.  I'm connected to a good 32A power supply.

If I set the power level for 10W, I can only get about 7W on these bands.  If I unplug the KPA100 and recheck the K2 alignment, I get more than 10W on all bands as stated above.  It seems as if the KPA100 attenuates the RF signal at frequencies above 18mhz.  I've inspected the low-pass filters for poor solder joints, incorrect number of windings or wrong parts.  Everything looks good to me.

Any ideas?

Regards
Rich