[Elecraft] K2 Faulty menu switch?

[Gerald Wolczanski]

Geeze, spent yesterday looking things over.  Put a piece of paper
between the encoder and the control board.  Thought I'd just put the
rig through its paces this morning and observe

1)  Well to start, the display flipped to the "side-tone level" after a
short time and a little later the encoder locked up and I was unable to
transmit.  In both cases, depressing the memory switch put the K2 back
in operation.

2)  Wondering if there was a time element involved, this morning, after
the anomaly cleared, I simulated operating by tapping the key every few
minutes.  The rig performed flawlessly for an hour.  The WSPR frequency
is the perfect place to test a rig - those guys don't even know I'm
there.

3)  Then I just left it on, listening to the band and checking every 20
or 30 minutes, and it's performed flawlessly for 4 hours so far.

4)  I don't believe in miracles - I'm mindful of Lenny's experience and
Don's advice.  Gonna leave the rig on and see if it acts up again. 

Jerry
KI4IO
Warrenton, VA




On Wed, 2022-10-19 at 12:46 -0400, w2bvh wrote:
> Had similar flaky symptoms on my 23 year  old K2. After careful
> visual 
> inspection it turned out to be a broken solder connection on the
> tuning 
> encoder. Wire barely broken off the encoder pin. Took 23 years to
> break!
> --Lenny W2BVH
> 
> On 10/15/2022 5:36 PM, Don Wilhelm wrote:
> > Jerry,
> > 
> > That does sound like it might be a bad solder connection.
> > Try resoldering Front Panel RP1 and U2.  Those components are
> > critical 
> > to decoding the switch matrix.
> > You might also try reseating Control Board U6 - but do so in a
> > static 
> > controlled manner.
> > 
> > With that 7xxx serial number, you might instead have a problem with
> > the FP Encoder board contacting the back of the Control Board which
> > causes "strange things" to happen.
> > Flush cut all leads on the encoder board (right through the solder 
> > fillet) and also on the Control Board where the encoder board could
> > contact.
> > As an extra measure, put an insulator (fish paper is best, but a
> > piece 
> > of card stock or better yet, a piece of flat plastic (like from
> > many 
> > forms of plastic packaging) between the encoder and the control
> > board.
> > 
> > 73,
> > Don W3FPR
> > 
> > On 10/12/2022 5:51 PM, Gerald Wolczanski wrote:
> > > from KI4io - Jerry Wolczanski
> > > 
> > > My K2 started exhibiting this problem in June and it's gotten
> > > worse.
> > > The LCD toggles rapidly between the frequency and the last menu
> > > used.
> > > A tap on the menu switch restores the display to normal.  It was
> > > quite
> > > infrequent to start, but now it's bothersome, happening every 10
> > > - 15
> > > minutes.
> > > 
> > > I re-flowed the switch contacts on the front-panel board this
> > > morning,
> > > but the problem persists.
> > > 
> > > Is this a switch issue or something else?
> > > 
> > > K2 S/N 7xxx
> > > 
> > > KI4IO
> > > Jerry Wolczanski
> > > Warrenton, VA
> > > 
> > 
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