Hi all,
I have a dual channel 3GHz SMU200A on my desk which shows "(B) Synthesis Reference PLL unlocked". Scoping A and B together they seem to be perfectly stable, I can move the phase in the reference dialog. Ref is on the loop between the SSYNs, removing the loop decouples A and B. Ref is also present on the back connector. Injecting an external reference doesn't make a difference. Service manual suggests changing A2240, I tried two other ones, same error. Internal adjustments pass fine.
All of this makes me think that I either don’t understand what is going on or I have an issue with the reference lock state being communicated correctly to the software.
R&S is its usual stony self, no help from them as no company. I posted in the groups.io R&S group as well.
Thanks,
Florian