Anritsu MS2721B / other non YIG spectrum analyzer block diagram or docs / parts

[EE-digger]

My MS2721B with LO error will be arriving shortly     It seems that schematic or even block diagram for many Anritsu products may be unobtanium.

Has anyone ever found any documentation for this family or, a block diagram for a non-YIG based spectrum analyzer.  After watching the videos from Shahriar and others, I suspect that this unit does not have a YIG / YTO.  Some failures of the crappy Micronetics VCOs have been found.  These things look like an SMD design with 1960's TV set point to point wiring and a bucket of solder.

I'd like to get a better understanding of how the 3 (or more) VCOs interact in their various RF source and conversion roles.

I've heard excellent things about Anritsu support but doubt that they sell component level items.  Any comment?

[dj9ss]

Hi,
I acquired a MS2721B which also showed the notorious VCO1 lock error.
According to Shariar's video, I had a closer look on the Micronetics VCOs.
Attached is a microscope picture of a large crack in a soldering joint inside one of thos VCOs.
After resoldering, the unit works fine, and the lock error is gone.
Regards, Jürgen