Ballast is a Venture MH ballast.

yep they both got Venture 120-277V ballasts.

oddly enough, the original ballast according to the fixture label was 277V but these were both wired for 240V with a red wire and a white wire. are the two voltages convertable among each other in some way?

BTW, see my handprint on the M-400A2? the paint is all powdery. I need to repaint them.

277v ballasts sometimes work on 240v so I guess someone decided to do that. I guess it's cause 277v fixtures are easier to find that 240v fixtures.

Also any dates on them, that might clue in as to when they were retrofitted.

the caps are too rusty to read. i remember the fixtures all being HPS, MV, and MH so it must've been sometime in the mid-2000s that they were retrofitted.

Hmm, I think Venture ballasts have a date on the label.

ok. I'll check tomorrow. off to sleep now... got a big day tomorrow... 1st day of school.

As for the ballast, if you don't mind 100w HPS you could always get this and transfer the stuff over. The pic even shows it having a power door plug.

I wish they still had the vented doors on these with the GE emblem on them. I have one of those ballasts but it's only 70 watts.