Hope this is helpful to someone…
(TL/DR = pretty simple fix for power and chroma issues)
I had asked some questions in another thread regarding issues with a Panasonic WJ MX30 and an MX50, but thought I’d just address this in a dedicated post.
Both boards had chroma issues (intermittently green-y to B&W), and the 50 eventually just died, and wouldn’t turn on. This is apparently very common with these boards over time. Did some research and found this dude’s videos:
Part 1: DEAD WJ-MX50 VISION MIXER PART1 - YouTube
Part 2: DEAD WJ-MX50 VISION MIXER PART2 - YouTube
So, with that and the assistance of the service manuals that I found on this site, I opened them up and tested the capacitors on the power board that he identified (on MX50 C10,C11,C18). They indeed had issues, so I replaced, and can confirm they now seem to work perfectly.
I believe the chroma issues were related to problems with the power board. This may strictly be my case though. I am certainly no expert.
Just wanted to post this to give people who are experiencing the same issues some hope. I know it would be helpful to me. A lot of people told me I should just write them off and find others that work, but it only took a few new capacitors to fix.
So thx to this community for posting links to the service manuals, and bless JVS VISUALS on YouTube. 
