[Elecraft] K1 with Issues

[Peter Wollan]

I read Chuck's description of his problem, and I thought, "What in the
world?"

Don Wilhelm deserves a round of applause for this diagnosis.

     Peter N8MHD


On 4/16/09, cstoverva at aol.com <cstoverva at aol.com> wrote:
>
>
> Hi Don,
>
> Your comment about using flux cleaner struck a nerve with me.? I didn't
> have any cleaner at the time of completion and obtained some a while back.?
> I don't remember exactly when.? I had an idle mind and hands one day and
> opened up the K1 to spiff things up.? I let it dry for a week and put it
> back together and it worked fine.
>
> The keying misbehaved a little during the previous use of the K1.? I
> cleaned the paddle contacts and reseated the plug and all seemed well.?
> Problem solved, or so I thought.? These two events probably relate.
>
> At first opportunity I will make the voltage checks and take a look under
> the key jack. I'll post the results.? Right now I'm off to install an
> antenna on my Volunteer Fire Departments new utility truck.
>
> Thanks.
>
> 73,? Chuck K4QS
>
>
>
>
>
>
>
> -----Original Message-----
> From: Don Wilhelm <w3fpr at embarqmail.com>
> To: cstoverva at aol.com
> Cc: elecraft at mailman.qth.net
> Sent: Thu, 16 Apr 2009 8:47 am
> Subject: Re: [Elecraft] K1 with Issues
>
>
>
>
>
>
>
>
>
> Chuck,?
> ?
>
> Make certain you have a dummy load connected to the K1 (it is
> transmitting) and continually tap the WPM- button to try to lower the
> power level for the testing that you need to do.?
> ?
>
> Theory:?
>
> The K1 uses one MCU pin (KEYIN) as an analog input to determine whether
> the dot paddle, dash paddle or both have been closed.  The resistors
> that determine the 3 levels are on the RF Board.?
>
> R19, R20, and 2 sections of RP5.  The voltage at pins 4 and 5 of RP5
> will determine the static voltage of all points in the circuit.?
> ?
>
> What to do:?
>
> Measure the voltage at pins 4 and 5 of RF Board RP5 and compare with the
> voltage at Front Panel U1 pin 5.  They should be the very close to the
> same voltage.  If not, check the values of R19 and R20 and re-flow the
> soldering of RP5, R19 and R20.?
> ?
>
> If you had ever attempted to clean the flux from your K1, that could be
> the cause.  If some flux cleaner residue wicked up under the key jack,
> it can create a leakage path which would explain your problem.  The only
> cure is to remove the key jack and clean both the board area under the
> jack and the bottom of the key jack.?
> ?
>
> It is conceivable that the key jack itself could have some kind of
> leakage path inside.  To check, you will have to remove the key jack and
> replace it if necessary.?
> ?
>
> Do the solder re-flow first - a bad connection can work fine for a
> while, and then fail later after a bit of oxidation occurs.  If that
> does not cure it, remove the key jack and check again with the jack
> out.  Replace the key jack if required.?
> ?
>
> 73,?
>
> Don W3FPR?
> ?
>
> cstoverva at aol.com wrote:?
>
> > My K1 (sn2450) went together back in Oct 07 without a hitch and has been
> working flawlessly ever since.?
>
> >?
>
> > A big glitch showed up tonight.? When I pushed the attenuator button it
> started transmitting dashes.? That cleared by cycling the power.? I then
> tried sending the content of memory 1.? It began sending that message,
> stopped, "end" appeared in the display, then started transmitting
> alternating dots and dashes.? When locked in transmit, the display blanks
> out.? Initially I verified that it was transmitting with another receiver,
> but now it seems to have lost output too.? It was hooked up to a resonant
> antenna or dummy load, so I wouldn't think the final fried.? I'm running it
> off a supply at 13.6VDC.?
> >?
>
> > A voltage check of RA3 pin 5 of the MCU shows 5.6V with both dot and dash
> contacts open.? When the WPM-/attn button is held the dashes start sending
> and the pin 5 voltage drops to 5.0 even? though the contacts are still
> open.?
>
> >?
>
> > I've been awake too long and not much is making sense, so I'm going to
> call it a night.? Any ideas or suggestions on where to look would be greatly
> appreciated.?
>
> >?
>
> > Chuck? K4QS
> > ______________________________________________________________?
>
> > Elecraft mailing list?
>
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft?
>
> > Help: http://mailman.qth.net/mmfaq.htm?
>
> > Post: mailto:Elecraft at mailman.qth.net?
>
> >?
>
> > This list hosted by: http://www.qsl.net?
>
> > Please help support this email list: http://www.qsl.net/donate.html?
>
> > ------------------------------------------------------------------------?
>
> >?
>
> >?
>
> > No virus found in this incoming message.?
>
> > Checked by AVG - www.avg.com
> > Version: 8.0.238 / Virus Database: 270.11.57/2060 - Release Date:
> 04/15/09 06:34:00?
>
> >?
>
> >
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>