Bought a massive Amiga 2000 collection tonight

[ral-clan]

This probably means you don't have an early startup menu (both mouse buttons while powering up), but can get it if you hold down the mouse buttons after the computer reboots to load WB2.1 or 3.0.

I can get a menu on power up by holding the mouse buttons down, it
lets me select either 68000 (MB, actually 68010 that was upgraded), the
68030 (accelerator card), or unix.

I get this menu before I get asked to select my kickstart version.

Okay, this seems to be a feature of the ROM on the accelerator card, but it's not the true Amiga Early Startup Menu, though I suspect you can get that after the computer reboots into a later kickstart version (i.e. hold down both mouse buttons while it does the reboot).

[PaulQ]

Be sure to check your battery for leakage, and remove it!

Otherwise, it will eat right through the motherboard.

Here's what mine looked like when I got my A2000:

[d0c]

did your amiga survive?