See comments on brackets
KR
Andrew
Andrew,
With the KPA100 installed, and the power set to 10 or 11 watts, what is
the actual power output in TUNE?
It should be near 2 watts. (True this is fine.)
If not, there is a problem in the VRFDET section of the KPA100 or in the
base K2.
First, remove the KPA100 (physically) and try it with just the base K2.
(Works fine)
If the base K2 is OK, then yoou have some KPA100 problem to solve. Put
the KPA100 upside down on a box or book about 1/2 the height of the K2
and remove the shield. ( All done works fine)
set the power to about 50 watts and prepare to do some voltage
measurements. ( 50 Watts set up)
(I will do this)
Measure the voltage at U5 pin 5 - then at 5 pin 7, they should be close
to the same voltage.
U6 pin 3 should be about 1/2 that voltage. If not, the problem is Q10
( Only see the problem after I put the PA back on the K2)
and possibly Q11.
If all OK this far, then make certain U6 pin 8 is near 5 volts.
If so, then check U6 pin 6 and tell me what the voltage there actually
is. U6 is a common failure.
73,
Don W3FPR
On 7/26/2026 1:16 PM, Andrew Lenton via Elecraft wrote:
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