5d Mirror not Coming Down!

I was shooting at a Bridal Shower and all of sudden the viewfinder goes black. I thought the mirror fell off, so i took off the lens and that wasnt the case. The mirror was in the lock up position. THen i took another shot and the mirror does not want to fully go back down!

Now i can take photos and shutter is great, exposure is good (had to use a light meter seeing that the camera does not meter because of the mirror). I can lock up the mirror and all the other stuff, but the mirror wont just go fully back down.

I need some knowledge on this problem. What brings the mirror back down? is it a spring?

Sounds like a trip to Canon repair is in order. You have a backup, right?

yes, i do have a back up. As for the camera, after extensive searching on the web i have come to the conclusion that it is a spring that brings the mirror back down.

And i was expecting the shutter to give, since its at 130k actuations. I didnt expect the mirror box to go!

This is well known problem with 5Dc, it's been addressed by Canon, under the warranty, if I'm not mistaken.
They'll be able to fix it, no doubt.
Other POTN 5D users will be able to help you about this problem more than me, I guess.

Too bad that it happened in the middle of the shoot thou, I can imagine how it felt..