Yeah, I've seen 3 different brands of 50" medium resolution monitors... Mitsubishi, Toshiba, and I believe Hitachi. They look very similar to a regular rear projection TV, but they only have BNC connectors for the R/G/B/Sync, and of course AC power. And yeah, Sega seemed to be big on using them.
For rejuvenating it... it's just like rejuvenating a regular CRT. Of course each tube is monochrome, so you follow the instructions for a monochrome tube, and I've found that even though some of the regular adapters fit, they're not the right pinout (a CR23 adapter fits my Top Skater, but of course has a different pinout). So, I just use my universal adapter, and the neckboards typically have the pinouts labeled, so I know where to install the pins. The setup charts don't usually have the tubes in them, but I've done fine by assuming everything is standard (6.3V heater, 50V G1). That may not be correct, but so far I haven't had any problems. Just do that for all three tubes and you're in good shape... and the picture comes out MUCH nicer. It doesn't really take much time to do... just take care when connecting the pins from the universal adapter.
DogP
For rejuvenating it... it's just like rejuvenating a regular CRT. Of course each tube is monochrome, so you follow the instructions for a monochrome tube, and I've found that even though some of the regular adapters fit, they're not the right pinout (a CR23 adapter fits my Top Skater, but of course has a different pinout). So, I just use my universal adapter, and the neckboards typically have the pinouts labeled, so I know where to install the pins. The setup charts don't usually have the tubes in them, but I've done fine by assuming everything is standard (6.3V heater, 50V G1). That may not be correct, but so far I haven't had any problems. Just do that for all three tubes and you're in good shape... and the picture comes out MUCH nicer. It doesn't really take much time to do... just take care when connecting the pins from the universal adapter.
DogP