Don, Thank you, with this it only took me 3 minutes to fix it with this info. The coverage on T5 was the critical factor here.
The good news is that I've spent the last 4 hours confirming that EVERYTHING else around the VCO is correct! 73, Thanks again! kc2vmp On Sat, Sep 28, 2013 at 5:11 PM, Don Wilhelm <[email protected]> wrote: > Rob, > > There is either too much inductance or too much capacity in the VFO > circuit - the high voltage means that the K2 is trying to reduce the > capacity to bring things into line. > > Count the turns on T5 very carefully. Each wire through the center counts > as one turn - a full wrap around the core equals 2 turns. > > If the T5 turns are correct, spread the red turns of T5 out as much as > possible to see if that resolves the problem. > > Worst case, you may have to remove a turn from T5. > > BTW, if you discover an extra turn on T5, you might want to count the > turns on the other toroids you have wound to be certain they contain the > right number of turns. Winding an extra turn on toroids is not uncommon > for builders with limited experience in winding toroids. > > 73, > Don W3FPR > > > On 9/28/2013 4:16 PM, Rob Gault wrote: > >> K2 #7449 VCO alignment difficulty. >> >> Cannot get 4.0 MHz R30 voltage to change at all - it measures 7.97V. Have >> confirmed all the cap values, varicap diodes are correct parts, T5 wound >> and wired correctly. >> >> Have scoped the area comparing to a second operational K2 & the wave forms >> look and behave the same as the rigs are tuned. The voltage on R30 is >> simply too high at 4.0 MHz. >> >> I set the K2 to 3.5MHz and adjusted L30 for the lowest voltage, this gave >> the following results: >> >> 3.50 4.14 4.00 7.97 >> 7.00 4.39 7.30 6.30 >> 10.00 5.08 10.15 5.86 >> 14.00 3.84 15.00 5.98 >> 18.00 4.42 18.20 4.67 >> 21.00 3.83 21.45 5.38 >> 24.80 5.92 25.00 6.40 >> 28.00 4.64 28.80 5.66 (29.70 6.87) >> >> Should I continue the build or what else should I check? >> >> THANKS & 73, Rob KC2VMP >> ______________________________**______________________________**__ >> Elecraft mailing list >> Home: >> http://mailman.qth.net/**mailman/listinfo/elecraft<http://mailman.qth.net/mailman/listinfo/elecraft> >> Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm> >> Post: mailto:[email protected].**net <[email protected]> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
