[Elecraft] Spurs on 6 meters on FT8 Barney K3LA

[Keith Trinity WE6R]

Did you re-set the Bias after changing finals and working on the KPA3 
and LPA?
1. The 8W vs 12W switch-over point on 6m is normal.
2. If the 6 pins for KPA3 DC power were darkened and you replaced with 
gold, you *MUST* also replace the corresponding KPAIO3 Riser-Board SOCKET!!
The socket gets cooked internally. Sometimes you can see blueing and 
heat damage, but not always.
3. Check C28 & C52 capacitors marked "M2" near the Finals output. Some 
older revs KPA3 they were mounted right between the Final tabs near C50 
& C51, they get cracked from thermal cycles and should be replaced and 
moved out away from the finals and mounted in-between the legs of 
C50&51. (If cracked, they usually cause spurs on 20m). Elecraft part # 
E530321
4. Make sure your WM HP cal number is good, typically 25-55, so the 
radio is not struggling to make more power than it should, then;
I recommend do a manual TX gain Cal at 50W on your main operating 
frequency because 6m is 4megs wide;
IE; "TECH MD" to "on",  TUN PWR" to "nor". Then make note of the number 
of "TXGN HP", Then set power to 50W exactly, set to your favorite 
frequency, then long press XMIT to do a TUNE for several seconds. Unkey 
and check the TXGN HP number. It may or may not change, but should be 
reasonable, typical numbers are 9 thru 60.
(You can do a 5.0w exactly if you like for the "LP" calibration)
*** Then never, ever, set to 5 or 50w exactly as you may do an 
inadvertent TX Gain Cal and mess up the numbers.
5. Try the internal 2-tone generator and look at the spectrum using 
that, maybe you are over-driving with the FT8 audio.
Keith WE6R Elecraft K3 Tech