[Elecraft] K3: Loss of speaker audio after DSP board upgrade

[Stephen Prior]

I received the upgrade DSP board today.  Swapping over the boards was very
straightforward, but on switching on the K3 I found I had no sound from the
built-in speaker (headphone audio was fine) unless I had the config option
set to run with headphones and speaker simultaneously. Therefore neither the
connection to the loudspeaker connection or the speaker itself are at fault.
No output from the rear speaker socket either.

I took it all apart and re-installed.  I could see no misalignment of
headers anywhere, nothing in fact which was in any way obviously a fault.
Put it back together again.  Problem still there.  Then I re-installed my
original DSP board (fortunately I had not been too hasty in returning it to
Elecraft!) and everything was fine.

Having assured myself that this was not a wider issue, I installed the
upgraded DSP board for the third time.  Now the speaker worked, but flexing
the DSP board slightly (with the left hand side cover removed) could make
the fault come and go.  Out came the new board again to check for dry
joints, cracked tracks, shorting metal bushes etc.  I could see nothing
wrong, although I know that hairline cracks are not easy to spot.

I put the new board back in for the fourth time and now the K3's speaker
seems to be reliable again.  I had looked at the mating of the pins, looked
to see whether there was any dirt there etc., all to no avail.  I would like
to think that I have somehow sorted the problem but have a sneaking
suspicion that it might come back to haunt me!

On the topic of the replacement board itself, I can see very little
difference between it and the Rev B board it replaced, however there is an
extra IC compared with my previous board. I was expecting a piggy-backed
board somewhere, but perhaps I have got the wrong impression from reading
this list about what has changed.  The audio is certainly fuller and easier
on the ear.


73 Stephen G4SJP

K3 #980