[Elecraft] MCU Load Failure w/FW 4.36 or 4.39

[Scott Prather]

I've been running FW 4.25 for some time now, primarily because there wasn't any compelling reason for me to upgrade. However, this evening when I saw Wayne's announcement for 4.39 I thought I'd give it a try. Unfortunately, I ran into an unusual problem.

I've installed FW dozens of times over the past three years that I've had the K3, and never once saw a FW failure until this evening. The K3 Utility begins loading 4.39 MCU, and when it gets to the point at which the utility invokes an MCU reset, nothing happens and the K3 Utility loses communication with the K3. Manually placing the K3 into the MCU load mode and restarting the K3 Utility was required to re-enable communications. I ran the loader again, and it failed the same way. Next, I tried to load 4.25, and the entire process ran through to completion without a problem. But if I try to load any FW above 4.25, the process always fails the MCU load at the MCU reset stage.

My K3 is an early serial number (early 200's), has the KXV3, KRX3, KPA3, KAT3 options, and I have the P3 (but no KPA500). I'm running the K3 Utility 1.4.4.25 on Windows 7 with a "real" serial port.

Any ideas what might be wrong? 

Tnx,

Scott
N7NB