mechanical box help

I just bought a dimitri box off ebay and got it in the mail today. The problem is, it will only fire when a battery is in the left compartment. If i put it on the right side, it wont fire, however, if i tighten the battery screw, touch a screw driver to the screw while touching the screw driver on the box body and push the botton, it works. So it only works on a short? Has anybody experienced something like this? Ive used a dimitri before and it was good, but something is off about this one. It doesnt seem right though considering how simplistic it is, and that the other side works....its all the same housing.

You have both batts positive up?

You are using two batteries, right?

Both batteries positive up, i would like to use 2 batteries, but the right side wont fire. Only a battery on the left gets it to fire.

I had the same problem with mine. The negative screws are too small for the threading on the bottom. The way I solved it was by putting some copper tape in the screw hole before threading the screws in. You don't have to have it wrapped all the way around, just enough so the screw makes better contact with the threading. Have not had a problems since doing this. Before getting the copper tape to do this I first used aluminum foil and then some strands of thin copper wire.