Discussion about the Korg PolySix synthesizer

hi folks, i am having an issue with my P6: i have put 2 3V lithium batteries in, hard soldered, and the machine will hold patches for a day. then, it dies, and the battery drops to about .1V.

i have been told that the circuit actually needs to have a ni-cad battery. will nickel-metal-something work? my local battery place has a chargeable nickel-something or other battery, but its not "nickel cadmium".

or do i have another problem not battery related? fyi, D15 and R91 is replaced as 1n4148's, and the elec capacitor removed, per the old crow site instructions. thanks so much for the help!-rj