Help diagnosing Motorola Quasar/WU821FS

I also have a Works in your drawers (works in what drawer) that had roughly the same vertical issue. Turned out to be low B+ supply voltage thanks to the multi section cap in the voltage doubler.
As a Motorola radio tech for 20+ years I can tell you that Motorola was very good at making "oddball" rating parts for good reasons. Your 50uf cap is one example along with other even number/odd value parts as we used to call them. Motorola wanted to keep the radio service within its own service depots and the wierd value parts was a way to keep you coming back. You will be happy to know that the pins and sockets used on the boards are still available for Motorola as they were used in the Micor unified base stations and micor mobile radios, these are a real troublespot for both the television sets and radios that used them.
Last to look for is to make sure that the regulated low B+ I believe is known as the 20 volt supply is right at 20 volts, anything above or below has caused me much grief with my STS-934 chassis including loss of color lock and vertical stability issues.

Is it MONDAY yet? Gotta get back to my bench!
Tech-109