[Elecraft] MCU LD

[Ron D'Eau Claire]

Also try forcing an MCU load (from page 45 of the owner's manual):

Forcing a Firmware Download
If you accidentally load an old or incompatible
firmware version and find the K3 unresponsive, do
the following: (1) unplug the K3 from the power
supply and wait 5 seconds; (2) plug the power
supply back in; (3) hold the K3's POWER switch
in; after about 10 seconds, you'll see the TX LED
flash (you'll also see MCU LD on the LCD); (4)
load the correct firmware version.

Ron AC7AC