[Elecraft] KPA500 MCU LOAD screen

[Andy Durbin]

"What is happening. ?   How can I clear this from happening?"

Do you have anything connected to the KPA500 "RS-232 PC" serial port?  When my KPA500 went into loader mode I traced the problem (with help from Jack) to corrupted RS-232 data that was being interpreted as the KPA500 loader command. 

>From the Programmers Ref doc - 

"D  - download firmware
The D command is used to download firmware to the KPA500. This command is for Elecraft internal use
only. Accidentally issuing a D command may require a rear panel power off for recovery."

My notes say:

"D results in KPA500 displaying MCU LOAD.   Recovery from accidental D requires rear power off, rear power on, then front panel power press."

In my case the corrupted data came from my Arduino based controller but I assume RFI could also cause the problem. 

73,
Andy, k3wyc