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.
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