I was gifted an XE-7 for my birthday a few weeks ago, and everything would be great, except that the shutter pretty much just does what it wants.

It worked without any problems at firstómy first roll had all 24 framesóbut I was missing a few from my second and my third (shot immediately after the second) was missing literally half the roll (12 out of 24). I thought that it was a sticking mirror at first (before getting the last two rolls processed), but if you fire the shutter with the back open, it's actually staying open. It makes no difference what the shutter speed is set to, even bulb. You fire the shutter, and it just stays open for an arbitrary length of time. I test fired it a few times earlier and had anywhere from 30 seconds to over a minute.

It was an eBay find, so I checked out the posting. The ad said that the camera had been professionally inspected, and there's a money-back guarantee. Is it possible for me to fix this myself or do I need to send the camera back? I hate to, but it doesn't seem like it would be worth the repair bill.