Don Et Al, So, It is with some embarrassment, and much relief, that I can report it was operator error and my BFO is now working perfectly. I got home from work and was getting ready to do some continuity checks to all the circuits surrounding and including U11, but decided I better check all the components again in that section with the RF board disconnected and out of the case. I found much to my chagrin I had not installed D37 and D38! I had them checked off in the manual as being installed, and I even wrote in pencil in the margin on the next step where you put the rest of the V149's in the RF board that I had 2 left over, but I failed to notice I had them left over because I did not put them in the step before!, good grief. Anyway I have a high BFO reading of 4917.60 and a low reading of 4911.98 with a difference of 5.62. Thank you Don and to others that gave suggestions, and I do wish those having similar problems well in their trouble shooting.
Upward and onward 73, Tom Bewick, K2BEW On Sun, Jan 20, 2019 at 8:22 AM Don Wilhelm <[email protected]> wrote: > Tom, > > Good work on the VFO. > Before you replace U11, measure the resistance from the wire on the > carrier board to the lead of the SMD IC. Do that for all pins. The PC > traces on the carrier board are not thru-plated holes and sometimes > become damaged with soldering. > > 73, > Don W3FPR > > On 1/19/2019 6:35 PM, K2bew wrote: > > Don et al, > > > > I tried a 15pf cap ( what I had on hand) at the source of Q19 to > > ground and I got .025v on R30 that did not change with the adjustment > > of L30, essentially no voltage. > > So, I took it off and it went back to 4.5 volts. So, then I tried > > Vicenç, EA3ADV's suggestion and I put 17 turns on the red wire of T5. > > That got me a voltage of 8.5V on R30 with L30 bottomed out that I > > was able to easily back off to a stable 6 volts. > > I went ahead and did the voltage tests on the other bands and had a > > nice range of 1.844 to 6 volts as my low and high on the VCO. > > So, that's all set. > > > > However, new problem. I went on to the test the BFO and I have 0000.04 > > kHz. on TP2, so it's not working. > > I went to the trouble shooting guide and I have 0.058 Vrms on pin 6 of > > U11 with the RF probe. > > Looking at the archives of the reflector that would indicate that U11 > > is bad and I need a replacement, correct? or are there other things I > > should look at first? > > The good thing is I'm becoming very accustomed to the radio and > > enjoying the trouble shooting. > > Thanks for all the help, I really appreciate it. > > > > 73, > > Tom Bewick, K2BEW > > > > ______________________________________________________________ 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 Message delivered to [email protected]
