Zorba owners/Help diagnosing display issues

Hello from Seattle everyone, I'm new to the list. I recently bought a Zorba on Ebay, which was my first machine as a kid back in 1985, dialing into BBSs and learning assembly and basic. I put a lot of hours in on this machine and was very excited to acquire one, even though the sale was 'as is'. I have some issues to address, beginning with perhaps a faulty component on the video board driving the crt. While I'm an experienced programmer and have some rudimentary skills with electronics, I'm going to be in bootcamp troubleshooting this board. I have some help in my network of friends, but wanted to throw this out to the list. Are there any Zorba owners who would be willing to trade notes/advice with me on their experiences troubleshooting hardware issues (or anyone else out there, for that matter :) )? Have you used the composite video out to feed another monitor? Detail on my first issue: the display appears to need the kind of stabilization I _thought_ the horizontal and vertical hold adjustments would provide, but it's not entirely stable. I have tried the composite out, feeding it to a cheap composite->HDMI adapter, but that signal looks like a blank screen in need of vert/horiz hold adjusting. Before I go much further, I was hoping someone out there might be able to verify their use of the composite out to an external display. I haven't found any detail on what that signal should look like, other than it's 'composite' - maybe someone with more expertise can tell me what assumptions I can make about a composite signal. Thanks for reading that long message - and glad to be a new member of the list. Ben