I'd appreciate suggestions that might help me isolate a problem that
I believe to be in the KPA100. Receive is fine on all bands.
My K2/100 has been working wonderfully for three years. Now,
suddenly, a problem appears on both on low and high power settings on
160-10mtrs. K2 Display shows, high current (briefly), high swr and
much below requested power even when feeding a 50 ohm dummy load.
Basic K2 checks out OK on RX and TX on all bands with QRP top installed.
The only section shown in the KPA100 schematic that would appear to
alter the desired rf flow in both low and high power settings would
be the SWR Bridge. No burned components visible so far. If the SWR
section is a likely candidate, would it be correct to suspect first
D16 and D17? Or could the T-R switch section be at fault based on
some of the anomalous voltage readings present.
Have completed voltage reading of D1-D14 and Q1-Q12 and U1-U7. Q4
and Q5 show lower than expected readings on TX. Other readings of
note: D7 -20 volts Anode and +19 volts Cathode, and D8 20 volts Anode.
Any suggestions for proceeding would be appreciated,
73, Jack, KT6JS
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