I don't know the construct of your battery compartment...but on the 210, 220 & 320 variety, the battery wires are crushed into the connectors...not soldered. If there is corrosion visible, it's also within. I had to solder directly to a smaller ground connection and avoid the main, circular ground connection, as it would not ground. Get yourself a pair of wires with aligator clips....consider an alternative battery pack (AAA's or AA's, etc)....upgrade the wiring or connections if you have to. I'm betting it's a ground. Good luck!