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 <w3...@embarqmail.com> To: cstove...@aol.com Cc: elecraft@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? ? cstove...@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:elecr...@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@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
