[Elecraft] KX3 - KPA100 communication problem

[Bernie Gardner]

I have a KX3 with KPA 100 and PX3.  They had worked fine until yesterday 
when communication between the KX3 and my computer through a KUSB failed 
when the KPA100 is on.  The KX3 talks to the computer fine when the 
amplifier is off, but as soon as I turn it on, either through the KX3 PA 
mode setting or with the switch on the amp, the connection to the 
computer fails.  I can communicate with the amp OK.  Also, the 
connection to the PX3 isn't lost but the speed drops from 38400 to 19200 
with the amp on.  The connections between the amp/radio/px3 are per the 
PX3 manual using Elecraft cables.

Thanks for any suggestions.

Bernie
W1AZ