[Elecraft] New KAT500/KPA500 owner needs help (K3/P3/KAT500/KPA500/Microkeyer II)

[Jeff Hall]

I just finished building my KAT500 and KPA500.  I am trying to integrate them into my existing setup consisting of a K3, P3, and Microham Microkeyer II.  This setup was working fine before I cabled up the new equipment, and now I am having some issues.
All hardware has been updated to the latest available firmware.
I have cabled the equipment as follows (as prescribed in the KAT500 manual, with the addition of the Elecraft Y-Cable so the KAT500 and MKII can access the ACC port on the K3):
KAT500:- ANT1 -> HexBeam feed- XMTR -> KPA500 RF OUTPUT- XCVR -> E850463 Aux Cable -> Elecraft Y-Cable -> K3 ACC (shares ACC w/microHam MicroKeyer II)- AMP  -> E8509463 Aux Cable -> KPA500 AUX- VDC  -> AC to DC 15V 1000 mA adapter

KPA500:- RF OUTPUT -> KAT500 XMTR- AUX      -> KAT500 AMP
MicroKeyer II - ACC -> Elecraft Y-Cable -> K3 ACC
K3:- ANT1 -> KPA500 RF INPUT
- I have set the KAT3 CONFIG menu to Bypass.- I enabled KAT500Y by tapping 1 on the KAT3 CONFIG menu.- KAT500 is in AUTO mode- Tuning power is set to 25W
- Power is set to PER BAND- I have used the KAT500 to memorize settings at the low, high, and midpoints of the bands I operate, and I selected the "Optimize for KPA500" setting in the KAT500 Utility program.
And the problems I am observing so far are:
- The KPA500 isn't talking to the K3 (or vice versa); band changes are not being tracked from either device- The KPA500 isn't amplifying any amount of drive (at 35 watts out of the K3, the first LED on the KPA500 lights.  Even with the OPER LED lit).- The KAT500 doesn't always power on.  Sometimes the K3 has to be on first.  Reconnecting the ACC port on the K3 seems to trigger this state.- The K3 isn't responding to mode changes in WinWarbler (RTTY/CW/SSB)
Something tells me I've got a problem with the ACC line and or cabling.
Thanks for any help you guys can provide!Jeff