If memory serves, That machine was a home version that was looked upon less that favorably and if we are talking about the same machine (bet those drunkards over there at P/side are all atwitter over the prospect Ken,)... My first thoughts would be reverse engineer it, carefully study it as a build and chase the problems down, most likely with nothing more elaborate than a good voltmeter. starting at the problem and working backwards... As for the flipper buttons, (and without even looking at it)a redesign wouldn't hurt , one would think, especially if it was to be converted to something like a Williams fliptronics.... Although that would get quite involved and would require a bit of skill and a decent workbench.