For a few weeks I've noticed it adding a couple seconds of time when it's counting down. It will get to 3...2...1 and then go back to 2...1...done. Didn't think much of it until the thing stopped working yesterday. The timer works fine, digital display is fine, but it will only heat for about 4 seconds and then stop. I'm no repairman so I'm wondering whether it's worth taking it in to get fixed or if I should just buy another oven. Opinions???