[Elecraft] KPA100 SWR adjustment problem

[Andrew]

I got to the part during KPA100 assembly where the SWR reading is =
adjusted.  With a 20W 50 ohm dummy load that has been tested good on =
other rigs, the K2 (with KPA100 attached) gives a 0.1 9.9-1 reading in =
tune mode with the power control set to 5.0 W.  The lowest SWR reading I =
can get by adjusting C1 is 7.0-1 (actually the only two readings I can =
get are 9.9-1 and 7.0-1, nothing in between).  By turning R26 and R27 =
fully counterclockwise, I can get a reading of 1.0-1, but the forward =
power remains at 0.1.  When I hook a DMM up to U5 pin 1, I see a minimum =
of about 35 mV with R26 and 27 at their midpoints, and a min. of 4.5 mV =
with R26/27 fully counterclockwise.  Receive seems to be fine on all =
bands with the antenna hooked up to the KPA100's jack.  Current in tune =
mode is about 900 mA, and about 400 mA in receive mode.  All of the =
tests done on the KPA100 up to this point have been fine, but I have not =
yet done any voltage checks (except the ones done during normal =
assembly).  Does anybody have any ideas?

Thanks & 73,
Andrew AC7CF
K2 1637
K1 508=20


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