Im still messing around with my new DX-959b and I checked the VCO circuit and it was set at 10.245. Is that off far enough to cause a problem with the PLL? I dialed it back to 10.240 just in case.
Yes sir. 5Kc off will screw the SSB to the point where it won't work properly.Im still messing around with my new DX-959b and I checked the VCO circuit and it was set at 10.245. Is that off far enough to cause a problem with the PLL? I dialed it back to 10.240 just in case.
I would.so im going to have to check all the other PLL settings now?
Check my other threads, i think i posted pics of the board the other day.Is it a surface mount circuit board? If not the alignment might not have changed.
IIRC, Xit13 pointed out that to remove C130 altogether and to replace D49 (a SVC251 varactor diode) with a 1S2687 varactor diode (used in the Cobra 148GTL and other Uniden chassis in its day - no longer available) to make it more stable. This will also slightly limit the range of the clarifier; but in turn will stiffen the loose drift.The Galaxy is the bandwidth of the drift. Exit Thirteen is the anti-drift expert. He has a fix for the drift problem. Just change out some caps to better quality and re-align.
I had a brand new 959 warmed up for an hour, did the alignments for AM and SSB and by the time I finished it had drifted about 20 Hz off of the set points. Still in specification but disappointing.
Maybe I'm Wrong here, but did you make sure to let everything warm up for a while before checking & adjusting?Im still messing around with my new DX-959b and I checked the VCO circuit and it was set at 10.245. Is that off far enough to cause a problem with the PLL? I dialed it back to 10.240 just in case.
That 'counter' in the MFJ wasn't meant to be used for definitive testing or alignments. It does not have enough resolution for alignment work. It displays only '27.385mhz' (for example); and not 27.385.000mhz - which is what you need to align radios.Yes, it had been on for over an hour. I checked it with the counter built into my MFJ antenna analyzer, so the accuracy may not be the best. I will check it later after my good Fluke counter gets back from the calibration lab.