Yeah, I'm almost positive it's the RAM. Yes, there are two of them, but also two other SIMMs next to the RAM (possibly VRAM?).

One of my SEs displayed a Sad Mac until I replaced its RAM, after which it worked fine, so I'll just do the same with the Centris and see what happens.

I actually think I have a few leftover SIMMs from when I bought the Centris some RAM, so I'll just use those.

I'll post back tomorrow with results!

-Apostrophe