I have had four or five Wallstreets pass through here, all with dead backup batteries and none with these symptoms. So I'm inclined to doubt that the backup battery is to blame.
Wallstreets do commonly have problems with the charge card (little card that sits under the trackpad), and one suspects that this is caused by poor quality capacitors. Were bad capacitors routinely installed on Wallstreet logic boards in general? You might try disassembly and cleaning/ inspection/ reconnecting everything. It's about an hour's work to strip down and then to reassemble a Wallstreet, so that and the cleaning would probably kill a good part of an afternoon. You'd need to strip it down, more or less, to install the backup battery, so why not do the whole thing?
