Teaberry Stalker XX unstable carrier offset

[Lkaskel]

Hi Everyone,
I dusted the Stalker off the shelf and wanted to do a quick test before I worked on the clock. The it sounded strange on TX so I went through the alignment to check things. The PLL alignment was fine until I got to the final stage. The 7.8025 and 7.7975 were verys unstable. They oscillate high and low. I checked the voltage at TR21 and they were within a few 10th's of what specd'. Would anyone have some thoughts?

 

[brandon7861]

I am pretty sure whoever wrote the voltages for node 8 was smoking crack.

Two things come to mind. #1, a bad switching diode. #2 is something I have done, swapped crystal filters and had to adjust for the different filter bandwidth.

 

[nomadradio]

CT1 and CT2 are subject to oxidation. I prefer to eavesdrop on the carrier oscillator when doing alignment. If you tune it in on a sideband receiver you'll hear scratchy erratic frequency jumps when turning the trimmer screw. We dribble a drop of control cleaner into the plastic trimmers and spin it a dozen or more times until it smooths out. And if yours has the white ceramic trimcaps instead of the plastic ones you might have to replace them to stabilize the carrier frequencies.

73