[Elecraft] K2 No Side Tone After Firmware Upgrade

[Don Wilhelm]

Chuck,

While both sidetone sources should be supported in 2.04P, go ahead and 
make the change anyway.  Yes, make the cut on the trace ging between 
U6-25 and Q5.  You will add 2 wires.  The one from U8-4 to Q5 (make 
certain you do not put it on the R-PAK) is the one important for the 
sidetone.  The long wire from U6 pin 25 and the capacitor is only used 
for data communications, and will not be used unless you have either the 
KIO2 or the KPA100, but add it anyway just for completeness.

After you make the change, the sidetone source will be only U8-4.  If 
you added the inductor and the resistor for the sidetone waveshape 
during the upgrade, check those components (and the trace cut) carefully 
if the sidetone still does not work.

73,
Don W3FPR

cstoverva at aol.com wrote:
>  Hi Don,
>
> This is K2 sn972 I'm upgrading, so it's an oldy.  The firmware chip is 2.04P which I somehow came into possession of while building my first K2 sn5939 a few years ago.  I had Elecraft send only the new I/O chip, so the firmware came to me in pieces.  I didn't see any notes about circuit modifications in the firmware documentation that I have.
>
> I do have the mods located on page 10 of the KIO2 manual.  Just to verify, when you say deletion, are you referring to the cut trace between U6-25 and Q5?  
>
> I own a .001uf cap, some hookup wire and an Exacto knife, so I should be able to knock this out in a few minutes.
>
> Thanks for pointing me in the right place.
>
> Chuck K4QS
>   
>