If you have issues after the battery replacement, take a look at the capacitors on the motherboard. If they are the original caps they probably are bulging and out of tolerance. Recap them with 1000uf/6.3V or even better 1000uf/10v.
Quoted from JethroP:Could be your computer power supply going out as well. Start by replacing the Prism battery. I have replacements. I'll PM you.
Here is the link to the Pinwiki section for batteries and right under is the motherboard cap locations and info. The motherboard battery is a standard CR2032, and the one in between the prism cards is a BR2325 coin style batteries.
https://www.pinwiki.com/wiki/index.php/Pinball_2000_Repair#CMOS_and_Prism_card_batteries
300px-Pin2KCapsCloseUp (resized).jpg
Oakdale, CA
