Works fine but doesn't charge

With a partially charged battery my 3DS works fine but it will not charge. I've checked the two fuses for continuity and they seem fine. With the unit plugged into the wall there is voltage going to the battery compartment until I insert a battery and then I read no voltage going in. I've tried with 3 different batteries. The original, a knockoff replacement, and a 3dsXL battery. Are there any other points to put my multimeter to get more information? Any other possible ideas or solutions?