What are the DC LO and AC LO values off the backplane? Do they change when you insert the CPU card. (one at a time).
On Mon, Oct 5, 2015 at 12:01 PM, Johnny Billquist <b...@update.uu.se> wrote: > On 2015-10-05 17:56, Henk Gooijen wrote: > >> -----Oorspronkelijk bericht----- From: Johnny Billquist Sent: Monday, >> October 05, 2015 5:44 PM To: cctalk@classiccmp.org Subject: Re: >> PDP-11/10 repair started >> Ok. I got the initial impression that you only had the CPU in. Thanks >> for the expanded info. >> >> When you don't have any core memory, I wonder if you might need bus >> grants in those slots as well...? It's not as if they aren't a part of >> the Unibus... Memory sits on the Unibus, just like everything else, >> remember? Needs to check further if any special wiring are in place for >> those slots, though. >> >> Johnny >> >> ========= >> >> I am not sure the "core slots" would need grant cards. The documentation >> is clear about slot 3-4-5 as SPC, needing grant cards. I never saw any >> doc where the core memory slots, when optional, but not installed, could >> be used as an SPC slot. I certainly am Not "trying" that ... >> I did try the system *with* the core slots filled with the correct boards >> but the behavior remained the same. >> To make fault finding not more complex, I removed the core board set. >> > > Ok. Not sure if it makes it more complex or not, but I guess it's not the > issue right now anyway. > > But my original comment about the behavior you described being very much > like what I've seen on other machines with bad/no termination still > applies. CPU seemingly stuck, but doing a master reset sortof gets it out. > But not functioning as it should. > > Well, no more ideas here at the moment. > > Johnny > > -- Bill vintagecomputer.net
