[Elecraft] Difficulty with K3 Utility RS232 Interface

[Lyle Johnson]

Hello Craig!

> The RS232 Application note states that "Do not use the metal shell of the
> RS232 or ACC connectors for chassis ground.  They are normally isolated from
> the chassis."...

The intent is to use pin 5 of the RS232 and the appropriate pins of the 
ACC interface, for signal ground and not to depend on shell-to-case 
bonding for passing signals.

> There is a deviance between the latest K3 schematic and my RS232 hardware.
> On both the RXD out and TXD in lines, my hardware has a 220 ohm resistor in
> series with the inductors.  No resistors are shown in the schematic.  Please
> clarify.

Early K3s had series resistors in the RS232 signal path. This is not a 
problem.

***

I suspected the issue you are having is related to the vast differences 
in version 2.02 (June 2008) usage of Front Panel Flash memory and the 
current usage of that memory.

I loaded my K3 with your version of code (MCU2.02, FPF 0.02, DSP 1.77). 
  Sure enough, I can't do a configuration file save, either.  I got the 
exact error message you are seeing.

I then loaded the latest versions with no problems, and successfully did 
a configuration save.

Thus, I think my suspicion of the differences in flash usage being 
responsible for your inability to do a configuration save is correct.

In general, when new, stable versions of code are released, consider 
updating at that time even if it has features you don't care about. 
Utility generally understands the recent versions and will handle the 
differences correctly.  After long periods, code cleanup or other 
measures may result in incompatibility with much older versions of firmware.

73,

Lyle KK7P