Simple battery replacement for most models of Zoom drum machines. This one is a ZOOM-323. In reference to the coin batteries I am talking about, I mistakenly say "3025" when I meant to say "2025" at one point...whoops. I meant to say that the 2030 and the 2025 are both 3 volts, but the 2030 is rated for a bit higher load. Below is the link for where I purchased the EXACT coin batteries you need for ZOOM-323 repair....the type with tacked on tabs.
3VDC Coin Battery (with tabs) link (Digikey part # is P657-ND):