PDP-11/10 repair started

Johnny Billquist bqt at update.uu.se
Mon Oct 5 11:01:34 CDT 2015

On 2015-10-05 17:56, Henk Gooijen wrote:
> -----Oorspronkelijk bericht----- From: Johnny Billquist Sent: Monday,
> October 05, 2015 5:44 PM To: cctalk at 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.


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