Steve, Based on your "sharp whack" cure, but yes, that does usually indicate a solder problem (or something loose). I would first check RFC15 on the bottom of the board - it is connected to pin 16 of U4 - check it with an ohmeter, even if it is open, it will measure 5 volts on both ends. Since your problem is intermittent, I could suppose that RFC15 is damaged, but not completely. If you suspect that at all, jumper it out temporarily and see if the problem ceases to occur.
Other things that can contribute to raspy TX audio are the KPA100 ribbon cable and its speaker cable. If this is a KPA100, be certain those are dressed as far away from the KSB2 board as possible. Remove the right side panel and tuck these cables up into the corner between the KPA100 front cover panel and the top of the control board. If neither of those steps correct the problem, it could be something following the PLL itself. Look at the schematic for the RF Board sheet 1 - everything to the right of U4 is a potential suspect and could deserve re-flowing the solder. 73, Don W3FPR Steve & Anne Ray wrote: > I have run into the first problem with my K2 S/N 1422, which has the latest > firmware and mods. I built it back in 2000 and not had any problems with > it till a few weeks ago. It now has an intermittent problem of receiving > and transmitting a very raspy audio. It is not caused by AC magnetic > coupling as I have no magnetic transformers near it. When the problem > occurs it will be on all bands and switching bands shows it is probably in > the pll. A good sharp wack on the case will make it disappear, so it > appears to be a poor solder connection. Needless to say when I open it up > and try and duplicate the problem by tapping on various components I cannot > make it occur. I have reheated all the connections around the pll > circuitry, with no success. The really aggravation is that this problem > will not show up for weeks and then start reoccurring. Any ideas? > > > > 73, > > Steve K4JPN > > > > ______________________________________________________________ > 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 > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.791 / Virus Database: 271.1.1/2763 - Release Date: 03/22/10 > 03:33:00 > > ______________________________________________________________ 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
