[Elecraft] K3 - stuck at MCU LD we upgrading software

[Lyle Johnson]

You may need to use the RS232 adapter cable in this case.

Lyle KK7P
> Tony,
>
> The usual reason for that is a glitch in the computer.  The fact that 
> the USB port is no longer detected points more to the computer than 
> the K3.
>
> Re-boot the computer, and see if it detects the USB adapter - that has 
> to happen first.  Even if the USB port is internal to a K3S, the same 
> thing applies, you must get the computer to recognize the USB adapter 
> and assign a COM port to it.  If the port is internal to the K3S, 
> power cycling may help as well.
>
> Then follow the instructions to "Force a firmware load" in either the 
> manual or in the K3 Utility Help file.
>
> 73,
> Don W3FPR
>
> On 1/28/2017 12:27 PM, N2TK, Tony wrote:
>>
>> Upgraded firmware from 5.54 to 5.56. The one K3 did it fine. The 
>> second K3
>> is hung up with the TX light flashing and the screen says "MCU LD".
>>
>> And the USB port is no longer detected.