I'm no monitor expert, but the best replacement would probably be an old style 1084. New style would work too, but you'd have to reach around back to switch the input button.
On the other hand, all my old 1084s died in the manner that you're describing, so those monitors are probably reaching their limits these days.
Maybe you could swap the faulty component from another monitor? It might be cheaper to get a scandoubler and go the SVGA route.
