I noticed back a few months ago that my Advantium 240 just wasn't working like it used to. I couldn't figure out what was wrong as all the heaters in it (ceramic, halogen, convection, and microwave) appeared to be functioning. The open light worked when you open the door but the "OVEN LIGHT" button when running the oven didn't work.

Finally, I did some research and found out how to put the thing in diagostic mode. Turns out there are TWO halogen bulbs in the top. One of mine was burned out. I ordered a new one at Christmas time but it was backordered and just came in.

Boy-oh-boy, GE couldn't make it any more difficult to change the thing. You have to remove the oven from the cabinet, remove the cover (22 screws), then remove two inner covers. You have to temporary remove a fan assembly. All this is another couple of dozen screws and four tabs you have to bend. Then you can unplug and remove the halogen bulb assembly. Some of the screws are not that easy to get to either. Thank heaven for my little magnetic retrieval tool.

Anyway, an hour or so later I have the thing back working as it should.

There's a pretty good training book on SCRIBD for the thing.