Why don't I replace the battery? Fear!
I don't want to be the one that broke the Harig controller. There's a VLB CPU daughterboard on there I don't want to touch. But you're right. I should at least cut out the nicad.
Here's the battery I bought:
NEW Tadiran TL-5242/W - 3.6 Volt 2100mA Lithium Battery | eBay
I think it has the right connector. I was not able to find the brand of motherboard that's in there. I looked through every one of the motherboard layouts I could find and no match. I'll have to get in there with a DMM to get the polarity right. If it works I'll post a picture. If it doesn't I'll post a picture of angry face.
Thanks,
Andrew