Carroll, Unless you are using someone else's email, it is neat to know that there is another Wilhelm in the K2 family - I started with SN 20 and it is still going strong.
If your RF Probe is anywhere near correct, it would seem that you have plenty of RF signal at TP2, so the problem must be in the counter itself. In the long past, there were problems with the gain of the 2N5179 transistors Q9 and Q10 on the control board - we thought that problem had been squashed, but perhaps it has reared its ugly head again. As a side note, I had purchased some stock 2N5179 transistors, (Fairchild manufacture), and found that they do not work well in the counter input circuit either, so that circuit is evidently sensitive to the transistor type and one 2N5179 is not necessarily like another for that application. If you have some 2N2222s around your workbench, try replacing the 2N5179s with 2N2222s. The counter high frequency limit may be reduced a bit, but if it is only used internally in the K2, the 40 MHz limit is not required, the highest frequency needed is less than 25 MHz. Contact [EMAIL PROTECTED] and I am certain you can have replacement transistors on their way to you. Just a side note - in your measurements of RF Voltage at Q24, it would seem that you crossed the gate and drain voltages. Check the lead orientation on the K2 schematic key and let us know if there was no typo. If you are truly getting RF Voltage on the drain, Q24 may be the problem (but then the K2 would have no transmit output in that case) 73, Don W3FPR > -----Original Message----- > > I finished construction of my K2 (serial #5400) last month and all was > working well. At the time of construction all of the filter > alignment went > well. It has been lots of fun... I'm selling my Yaesu. :-) > > Since then I decided to calibrate the VFO on my K2 to get the frequency > better aligned. I don't have an accurate frequency generator so followed > the instructions in the manual and used WWV as my source. That all went > fine but when I went into Cal Fil and wanted to make a change to > one of the > filters got an 'info 230' message. I searched the list and found that was > related to the microprocessor not seeing the BFO frequency during a CAL > FIL. I verified that the frequency probe works by doing a CAL > FCTR with the > probe on TP1. When I move it to TP2 it always shows 00000.00. > When I first > aligned it last month it worked but not now. > > So... I checked the following... I verified that Q24 is getting turned on > via V ALC when CAL FCTR is enabled. I see 7.26V DC when V ALC is on, zero > otherwise. > > Used my RF probe to find the following RMS voltages for Q24. > > V ALC On > Q24 drain 5.99 V > Q24 source 2.02 V > Q24 gate 0 V > > V ALC off > Q24 drain 9 mv > Q24 source 15 mV > Q24 gate 0 V > > > It looks like the FET is turning on and off according to V ALC. I used my > scope to look at TP2 and can see a nicely formed wave form at around 4Mhz, > But can't detect it with the internal frequency counter and probe. So to > verify the probe and counter works I used the frequency probe to verify > 04913.34 MHz on pin 6 of U11 but it shows 00000.00 when moved back to TP2 > Really confusing... > > Nothing jumps out at me. Its been years since I did any serious > troubleshooting. :-) Anybody have any ideas about what I can do? > > 73, > > Carroll (W7CSW) > _______________________________________________ > 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 > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.394 / Virus Database: 268.10.4/401 - Release Date: 7/26/2006 > > _______________________________________________ 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
