OK, I had the PDP-11/23+ board in place, and the system loaded up. I was testing out the memory boards I've got by swapping them in. It didn't seem to like a pair of clearpoint memory boards I've got, and then I put in the M8637-EC board, and NOTHING works. It won't even come up with the info on the /23+ ROM. I've a very bad feeling about having put ECC RAM in it. I went so far as to pull out all the boards, nothing. I swapped the /23+ with a /73 and still nothing! What on earth did I do? The diagnostic LEDs on the /23+ are D1, D2, and D4 unfortunatly the manual I've got on the board doesn't seem to explain what the LEDs mean. It's as if I managed to fry the backplane, but that really doesn't make sense. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)ix.netcom.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.dragonfire.net/~healyzh/ |