It looks like classic PTTL (poorly tinned toroid leads) on T5. Vic 4X6GP
> On 9 Jun 2017, at 5:20, Robert Forster <robert.fors...@gmail.com> wrote: > > Hi Don and Group, > > I got a bit of time to troubleshoot this evening. > > I do have a good signal at TP3 so I am ignoring the PLL and U4. > > I did the DC measurements at Q18 and found some issues. > > the gate shows as a negative polarity but at -.001 volts > Source is .08 > Drain is at 6.8 > > This should lead me to suspect T5 correct? > the soldering on the underside of the board for T5 looks ok (no ring for > these points but the topside of the board looks rough! I used the USB > microscope and took some photos. > Here: https://flic.kr/s/aHsm2aNdeG > > I'm thinking that after the VHF contest I should remove T5 and check the > windings and re strip the ends and retin. Does this sound like an > apropriate course of action? > > Oh and just for the hell of it I bypassed C60 with no effect either. > > Thanks again for all your help! > > 73, > Robert > AD0TA > >> On Wed, Jun 7, 2017 at 6:33 AM, Don Wilhelm <donw...@embarqmail.com> wrote: >> >> Robert, >> >> Do you have a good signal at TP3? If so, ignore the PLL Reference >> oscillator and U4 for now. >> >> You need to get the VFO operating before doing anything else. >> Do the DC measurements a Q18. If you do not have a negative voltage at >> the gate, it is not oscillating. >> >> T5 is the most likely problem with the VFO. Make certain it is wound >> correctly and the leads are well stripped and tinned. If you see a ring >> around the lead (on the solder side), that lead was not adequately stripped >> and tinned. Both windings must be wound in the same direction. >> >> If all the above is correct, put a temporary jumper across C60 to disable >> the VFO ALC circuit. If it oscillates with the jumper in place, but not >> without it, replace Q17. If that still does not correct it, try replacing >> Q16. Be certain D11 is oriented correctly. >> >> Ignore the voltages on U4 pins 5, 6, and 7 - those are digital signals, >> and the manual lists the voltage for the active signal, not what you would >> typically measure with a DMM. If you look at them with a 'scope you can >> see pulses on those lines, and that should be sufficient for proper >> operation. >> >> RFC 15 also needs to be ignored until after you get the VFO operating. >> Once you get a VFO signal at TP1, then you can investigate the operation of >> U4. >> >> 73, >> Don W3FPR >> >> >>> On 6/6/2017 9:47 PM, Robert Forster wrote: >>> >>> Hello to the group! >>> >>> I'm afraid I need to lean on your collective K2 troubleshooting expertise. >>> After a long break I have finally made it to the Alignment and Test Part 2 >>> of my build. Everything was going OK until I got to the VCO Test. I have >>> no signal at TP1. I have tested this with the built in counter as well as >>> an external counter. I have gone through some of the troubleshooting I >>> could find online: >>> >>> The orientation of D13 and D8 look good >>> >>> I have checked the soldering at relays K13, K14 and K15 and the value of >>> C72. >>> >>> I have checked the varactors at D21 through D26 and they are oriented >>> properly I am nearly certain they are all the correct type >>> >>> I tested RFC15 in the circuit and could not get any continuity through it. >>> When I pulled it out of the circuit it tested fine so I put it back in. >>> I'm sure this is something basic I just dont understand. >>> >>> I know there is some more testing I can do with Q17 and Q18 (I did check >>> that they are the right type and orientation I also check all the >>> component >>> values around Q18) Lets set that aside for just a second though... >>> >>> Here is where I think it gets a little weird. Looking at the schematic I >>> followed it back to U4. When I compared the voltage table to what i was >>> actually seeing on U4 I think I may have found my problem. According to >>> the table pin 7 should have 0 Volts but i'm showing 4.8! It also shows >>> that pin 13 should have 4 volts but I'm showing 0. All other pins are >>> normal and match the chart. >>> >>> Following Pin 7 of U4 back to Pin 1 of U5 I see the same 4.8 volts. >>> This is supposed to be a clock line so I'm confused where this sort of >>> voltage would be comming from. >>> >>> I'm still new to alot of this and this is by far the most complex kit I've >>> taken on so any and all help will be appreciated! >>> >>> Thanks and 73, >>> Robert >>> AD0TA >>> >>> >>> >>> > > > -- > === > I could tell you a UDP joke, but you might not get it. > === > ______________________________________________________________ > 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 > Message delivered to k2vco....@gmail.com ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
