Proper grounding of Japanese JAMMA cabinets

[ophtho4]

I've got two Japanese sit down JAMMA cabinets (a Jaleco Pony IV and a Sega New Astro City). Problem is that the plug coming out of both of them has no ground. Has anybody attempted to properly ground these import cabinets and is it really necessary ? Obviously I'm stilll alive and so are others, but I do get slight tingling sometimes when touching the bare metal of the cabinet on the inside (I'm far away from the monitor), so its clear its not an ideal situation. Also, if it is necesaary are there any other resources out there for doing it properly other than the Bob Roberts grounding page ? I'd like something more specific for the task at hand, but I guess I will go with whatever is available

[kenzo42]

ground thru the chassis screw on the back, near the power cord, via a cord connected to the wall outplet screw.