[Elecraft] K2

[Don Wilhelm]

Larry,

Since you asked 'why' - U2 pin 13 connects to the "D2" button encoding 
line - the buttons that use this line are BAND+ and the AGC/CW REV 
buttons.  Any unsoldered connection along any point of a signal line 
will cause the same behavior (one must connect all ends of the wires, 
even if the wire is actually a PC board trace).

If there was a slight contact between the pin and the solder pad, it 
would likely work sometimes.  Such is the nature of unsoldered 
connections.  I have seen them work for years and then suddenly develop 
enough oxidation to stop working.

73,
Don W3FPR

L. D. Ingram wrote:
>
> Hi,
>
> I received a note from Don W3FPR and Hank  K8DD about the problem I 
> posted the other day where even when I just tapped the band up button 
> on my recently built K2 it would sometimes go into the RCL mode.
>
> First I want to say thanks for the suggestions and then tell you what 
> I found in case someone else has this trouble. It was the usual, a bad 
> solder joint, but not where you would expect it. What happened is U2 
> pin13 was left floating because the trace from RP1 went through the 
> common terminals on the AGC switch and one of those was not making a 
> good connection. Once I got voltage back on pin 13 of U2 everything 
> worked. The puzzling thing is why it worked most of the time with that 
> pin floating.
>
> Thanks again.
>
>