Batteries test okay with good voltage individually? Are you using the handle, aluminum cover, and long screw to conduct POS or NEG to the board? Brad's configuration supplies 3V POS via the handle, cover, and long screw to the circuit. On the other end pf the handle the battery contact springs provided the ground to the circuit. Also, does the very butt end of the handle have paint on it, enough to interrupt a good contact with the aluminum cover?
Yes, I’ve recharged and tested the batteries several times. In a previous test with just the raw positive/negative wires touching the batteries, I got proper lights/sound. After that, I began working to test-fit the circuit inside the P2 body, with springs acting as the contacts.
I was going with Nicksdad’s suggested configuration, with the two lithium-ion batteries stacked on one side of the handle, positive end contacting the inside of the aluminum handle buttplate. On the other side, the negative wire is connected to a spring which also makes contact with the buttplate, thus using the the plate itself to complete the circuit.
As noted, however, a number of wires came loose from the board due to all the handling, and had to be resoldered. I wonder if that has something to do with the current problem. Because, when I took it back to just touching the pos/neg wires to the ends of the batteries, I got nothing.
And, yes, I should probably give the edge of the handle a good sanding, just to make sure that the buttplate makes contact.