With a few helpfull tips from Don Wilhelm - W3FPR I was able to quickly resolve my K2 power output problem.
The voltage measured at diode D9 cathode (marked end) on the RF board was 2.30 volts DC. After R66 (2.7K) it was 0.0 volts. The microprocessor was NOT getting the RF output signal via VRFDET. The interal RF output meter was not indicating any output power. During the build I installed the RG174 coax at signal "RF" for the K60XV Rework Eliminator. When soldering the braid on the other end to L4 the center conductor shorted to the braid grounding the signal from D9 - operator error. Correcting that problem I now get 10 watts out at 2.1 amps on 40 meters with the power control set to 10 watts. The power control changes the output power. The internal RF output meter now displays output power correctly. I am now proceeding to complete the Part III test. Best, Joe Szczubelek - K9DMV --- Don Wilhelm <[EMAIL PROTECTED]> wrote: > Joe, > > The initial problem to be solved is that there is no > indication of power > output being fed back to the K2 microprocessor. > > The most likely source is a bad solder connection > and the second most likely > is a misplaced component. > > Keep your testing periods short, ignore the high > current messages for now, > and proceed as follows: > Start your search at RF Board diode D9 - if all is > well at that point, there > will be a DC voltage during transmit periods - how > large it is depends on > the amount of RF output, for now just be certain you > have a good solid DC > voltage there - anything over a volt or so will > indicate that the RF Output > Detector is working. > > Next point is on the Control Board - the VFRDET > signal which appears at pin > 10 of P4 - the DC voltage during transmit should be > about the same as you > measured at the cathode of D9. > > Lastly, check the VRFDET signal at the > microprocessor - U6 pin 2. The > voltage should be about the same as at P4 pin 10 if > R12 is properly in > place. > > Let us know where the VRFDET signal path is broken. > > 73, > Don W3FPR > > > -----Original Message----- > > > > The build for K2 ser # 5628 has been going well > until > > I got to the "Alignment and Test Part III" 40 > meter > > transmitter alignment section. > > > > Problem: > > > > With current set to 2.0 AMPS and the power control > > fully CCW I measured 7 watts on an external > wattmeter. > > The internal wattmeter had NO indication. When I > press > > the "tune" control with the display set for > voltage > > and current I see 13.3 volts and 1.88 amps. The > > current will start to slowly rise at .02 amps per > > second and will reach 2.00 amps in about 10 > seconds > > and the "HI CURRENT" message will appear with 7 > watts > > output. > > > > > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.430 / Virus Database: 268.15.6/567 - > Release Date: 12/4/2006 > 7:18 AM > > ____________________________________________________________________________________ Any questions? Get answers on any topic at www.Answers.yahoo.com. Try it now. _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
