*Coughs*
Bingo pinballs.
That's said, I've worked on a number of Grand Prix games and a lot of Bally games from that era. Bally thought more about the technician, in my opinion, than Williams, and I vastly prefer Night Rider to Grand Prix from a gameplay perspective.
Some Bally EM thoughts:
50v for everything makes life pretty simple.
Stepper design is superior
Score reel design is very similar, but Bally is the template in my head for easy to repair score reel. Nylon parts are simple to clean and reuse.
Relay banks and playfield items generally have a nice separation (unlike late model Williams).
Lamp sockets are generally not bad unless you're working on a bingo... Compared to a Gottlieb lamp strip with a bad socket, geez.
Jones plugs do get a lot of hate. I like their Jones Plug design, but the Williams is more solid, but the Williams female plugs are harder to clean.
Relay board lifts out easily and relays are elevated to keep general dirt off.
Their fuse blocks, though, are sometimes bent out of shape from heat. I see this much more often on bingos.
Anyway, I know this is moot, but just some repair thoughts.
I personally really really dislike the way that relays are stacked on the back of the playfield on Grand Prix.
The steppers mounted so close to the apron are also a bit irritating and I've worked on two now that have had their stepper spiders bent (from someone less-than-carefully handling that).
If anyone spills a beer in a Williams of this era, it all tends to fall on the fuse block for some reason. but the all-metal dual clip design is mechanically superior.
Quoted from EMsInKC:The Bally jones plug issue is about like the Bally lamp socket issue. Much exaggerated. I've had way more issues with Gottlieb lamp sockets than I've ever had with Bally sockets. Never had an issue with a Bally jones plug either.
Oh, just saw this - just reiterating at this point, but I've worked on Bally games where the plug has broken on one female pin. A bit irritating, but not the end of the world. You're talking a max of 24 (48 if you desolder wires first) to solder.