[Elecraft] KAT or KPA Issue, Likely KPA

Byron Peebles NZ3O at arrl.net
Tue Oct 25 18:22:27 EDT 2016


Thanks to all who have sent suggestions on how I might resolve my "KAT 
Not Tuning" issue.

Here's what I think I know so far:

1. The KAT seems fine.
2. The P3 Output Monitor thinks it sees 0.6W on the antenna line after 
the KAT.
3. This implies to me that the K3S thinks it is tuning with 25W, but it 
isn't.
4. This implies that the KAT isn't tuning due to low drive (and maybe 
it's already tuned).

5. Last night when I ran one of the Utilities, probably the KPA one, I 
though I saw an Fxx code streaming into the text box on the MACRO tab of 
the utility.  I thought it might be F00F00F00, but I'm not sure.  That 
could be some communications error between the KPA and the K3S, but it 
isn't happening now.

6. The HIGH SWR display at the K3S is 11:1 plus/minus in TUNE (25W) when 
the KPA is STANDBY and 9:1 plus/minus when in OPERATE and 15:1 when the 
KPA is OFF.  In all three situations the K3S thinks it is outputting 25 
watts, but it doesn't seem to be.

7. If I key the radio in KPA OPERATE it looks like the KPA is outputting 
30 or 40 watts if you trust the display.  Varying the K3S output doesn't 
have a corresponding change in KPA display, it just moves from 30 to 40 
to 30 out. That happened once but I cannot repeat that test result.

8. I have powered-off the KPA with the rear switch and discconected "the 
mains".  This should have reset any hard faults.

9. The FAULT LOG shows the last error as "60V Supply Over limit" if the 
latest is at the top, or "Excessive Reflect4ed Power (High SWR)" if the 
latest is at the bottom.  There is no timestamp so I cannot be sure when 
these occurred, but an occasional HIGH SWR happens as I tune and fiddle 
with antennas.  (Sometimes I forget to retune a segment.)

Should I suspect control cable issues or something internal to the KPA?

Thanks, and 73, Byron



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