VAX 11/780 progress ... just a little

From: Gunther Schadow <>
Date: Thu Sep 25 12:37:19 2003

Johnny Billquist wrote:
> To make a short answer: the unibus termination is *vital*.
> If you fail diagnostics with it inserted, it's not because of the
> termination, but because some problem in your Unibus don't show up
> otherwise. The termination should be in the last slot, in AB.

So, I need grants and NPG grants in front of the terminator?
When I plug the terminator directly behind the UDA50 (which
happens to be the last card) things are even worse. The reason
I don't trust that terminator is that two of the 3 small
capacitors seem to have been damaged on the edge. So, may be
it creates noise on the bus? How can I test that the terminator
works properly?

Ahh, but that is not properly installed, right? If I have a
9 slot UNIBUS backplane, then only the last slot (A,B) can
have the terminator, right? So, I should put in more cards
and grants in slots 7 and 8, right? Do I need to put a grant
also in slot 9C (since the terminator is only in 9A and B)?

thanks for your help,
Received on Thu Sep 25 2003 - 12:37:19 BST

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