[Elecraft] K3/KPA500/KAT500 Problem-Need Help

[Gary Ferdinand]

When going to a high band (15, 10) from another, with the KAT presenting < 1.1 SWR to the KPA, I am getting a KPA fault 11 (power amplifiers are dissipating excessive power) and sometimes the "Hi SWR" fault.  As I watch the LEDs on the KPA, what I see on the first dot sent is the red fault light, the LCD description AND full red bars on the SWR KPA display.  The KAT display shows the 1.2 green light at all times. The second dot (after a fault reset) shows normal KPA operation.  The KAT is operated in MAN mode with a L/C setting previously established.

Am I having an issue with the amplifier disable before the tuner has settled?  Or?  The SWR as displayed by the KAT utility is approx 5:1 on 10 and as high as 7:1 on 15 (antenna side of the KAT).  

For other than six, looking outbound from the KAT, is RG213 to a DXE AT 4:1 balun, to approx 60' of open wire line at a nominal 580 ohms.  CM chokes exist in the open wire line on the antenna side of the balun. LadderSnaps are used as spacers.  The radiator is a 160 meter dipole, full length, in the clear from end to end.  The firmware on the KPA is 1.33 (though it behaved similarly on 1.32 and whatever shipped with it).  The firmware on the KAT is 1.41.  The firmware on the K3 is 4.67.

So the question:  Why am I getting a KPA fault on the first dot after a band change on at least 10 and 15? Needless to say my KPA log is full of fault 11s.  My band change routine is:  select band, send a dot, clear the fault, operate.  Not what I was hoping for.

Tnx for any help.  73,

Gary W2CS