I have the same set that the OP has that Hal posted a picture of. Mine just bit the dust. I have the same little daughter board with the two little batteries, but those aren't the ones that died. There's a CR2045 under that piezo. Mine had tabs spot welded to the battery and no one would make one up for me, and I didn't feel like waiting weeks for some chinese battery that -might- work. So being the ingenious little devil I am, I desoldered a CR2032 cmos battery holder off an old computer motherboard I had laying around, the tabs almost lined up perfectly, and soldered it into the set. Presto. It works again. I just set the piezo back on top of the battery, no glue. its all plastic so I wasn't worried about it shorting out.
