"Regardless, it's always smart to replace any MTH white, 8.4 volt battery before ever starting up any PS1 or 5 volt PS2 engine."
Like Norton says, use a new, fully charged, NiCad or NiMH 8.4 volt rechargeable battery.
A couple of folks that I respect greatly have advised me not to use a BCR with a PS2 5 volt board. (Regardless, BCRs are fine with the 3 volt PS2 boards.)