I hate it when I do this. So I started playing around with the 11/34 and discover that 2 bits aren't being set on the words I try to load into memory. I guess it is perhaps bad memory, I don't have a way to test it other than to load in a program from the front panel, so I pull the memory and replace it with 64KW that are known to be good. Now it shows the top 4 bits as being stuck on. I pull the memory, blow out the connectors, look for loose dirt etc that I've missed, reseat the memory but no joy. Everything else seems to be working so the next suspect is the KY-11B, if it had lost a buffer it could exhibit this behaviour. I pull the KY-11B and check it out, it looks ok so I clean out the connectors where it is seated and re-install. No joy, 4 bits stuck. Now I'm really irritated, so I take the KY11B from my working 11/34 and replace it, great all the bits work. Ok so I've got a KY11B to fix. Not too much of a problem since it is pretty simple. I put back the original memory and now I get BUS ERR whenever I try to touch memory. Ok, figure the memory board was bad and put the good board back in so that I can work on the RL11 but wait, now it also gives me a BUS ERR indication. I check to make sure I haven't dislodged any of the stubby grant cards, they are fine, pull the terminator and move it up to the end of the first back plane. Still I get the BUS ERR indication. ARGH! --Chuck