The fan swap from external vent to internal was a snap.
Getting the old one down, was a brute. Those things are heavy. I had to go out and buy a drill bit and some toggle bolts and I was little worried by how many holes the wall and cabinet now has, but we got the new one in. It was almost as hard getting the new one in.
The "new" one (which is actually from 2005) has a dial control that we'll have to get used to. It's also an normal oven too, but I don't think we'll use that feature. But for less than the price of a repair guy, and a days of work and heavy lifting by both me and G, we have a microwave again.
Yay! and thank you avacon and spouse (I'm not sure I have her lj name)!
I didn't reinstall the top stainless steel plate before taking these photos:
The interior bulb seems to have not survived the transportation and it's officially not user serviceable and would require taking the oven down from the wall again to get at it! Way to go GE. Yeesh. There are some people on the web who think it's possible to do with it mounted and by the user if I can just figure out the part number.