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

[Don Wilhelm]

Jimmy,

You should see little voltage sag on transmit, especially at QRP levels.

Compare the voltage directly at your power supply terminals between 
receive and transmit.  If it stays up, then check your power cable to 
the K3 for adequate size wire and good connections.  If you have a DC 
power distribution device like the RigRunner, remove the K3 from it and 
connect direct from the power supply to the K3.

OTOH, if the voltage at the terminals droops during transmit, open the 
power supply cover and remove the bolt terminals - clean the solder lugs 
on the inside and the bolts, then reassemble making certain the bolts 
are tight.  If those bolts turn even a little bit when tightening the 
external bolts, they are not tight.  You must have tight connections at 
the power supply.

73,
Don W3FPR

On 1/28/2017 3:49 PM, James Walker wrote:
> Yours is not the Astron power supply I was using. Mine was the 35A, transformer style, not switching, with dual meters. I’m still using it for other radios with no problem. And yes, I did check the voltage reading on the K3/100 and it did reduce severely under any load, even QRP. That’s a strange quirk in the equipment but I think that’s it.
>
> Jimmy Walker
> WA4ILO
> Macon, GA
>