[Elecraft] Trying to use KPA-1500 on 160

[N4ZR]

New owner trying to get ready for the CQWW 160 contest.  Rig is a K3 
with the Aux cable connected.  When the amp is in Standby mode, using a 
dummy load, I'm readily able to deliver 30 watts CW (or 50 or 100) on 
160 with the tuner bypassed or in. However, as soon as I switch the amp 
to Operate, and send my first dash, I get a hard fault with the LCD 
message input power 67 watts.

I'm guessing it might be a K3 adjustment, but I don't know where to 
look. Any advice much appreciated!

73, Pete N4ZR
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