... because I just dropped an LCD into my MultiWilliams.
The WG4900 I had in there died and after running RandyF's flowchart I am at a loss. Dropped a spare WG7900 in, but it has convergence issues and I lack the patience to sort it out. jrok's MW board can be switched to output VGA, so I wired up the video from the JAMMA harness to a VGA connector, dropped in a spare LCD monitor (with an available 4:3 setting) and the problem is solved.
It isn't authentic (no matter what that belligerent KoolAid man says). It doesn't look quite right. But it works and was completely painless.
May the purist gods forgive me, I am really tired of fixing old monitors.