Like Chad said you can rotate the batteries and see if it comes to life. Cleaning all the contacts in there with a little sandpaper is a good way to go too. Try not to cheap out on batteries, lithiums are WELL worth the extra money in these units.
Failing all that, send it to AIM and they will probably have it back to you in under a week. Worth doing since getting the same data from a MC4 is going to cost a few hundred bucks.