For those who didn't catch it: https://www.ebay.com/itm/202415330983 I have bought from this seller before (very happy with the results), but am not otherwise affiliated. The -11/04 is a nice UNIBUS starter/test machine (my UNIBUS board debug machine is an -11/04). The CPU is a single (hex) board, and it's really simple and straightforward - very easy to work on and fix. (You don't even need to put it on an extender card! :-) Depending on the backplane that's in the machine, it might be super-easy to upgrade to an -11/34 (if it's a DD11-P, as many /04's are, just pull the CPU card and plug in a set of /34 boards). Not sure what's up with the M105/M7821; they aren't standalone cards, but go with some other card (they are addressing and interrupt/vector functionality). No idea what it was, though... Noel