Any Tech 2 users here?

I hooked our tech2 at work up to my new to me truck to see what I could pull out of it and to try to turn the key in ign. chime off and it blew the fuse on the tech2. tried it again same thing popped the fuse. So I changed it and put it away. We just had it updated it the other day and I dont know if they screwed it up or if its the truck. any ideas why its did this I haven't gotten to work on too many newer GM's at work we have mostly older ones and fords and dodges.