1 Oct
2014
1 Oct
'14
6:23 a.m.
On Oct 1, 2014, at 8:42 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
Maybe I'm thinking of a different board; it's been a while since I
looked at my BDV11, and it looks like it indeed does not have
removable terminator packs. Not sure why I thought it did... that's
an odd brain fart.
From: David
Riley
> But not all quad cards have removable grant
jumpers - e.g. the BDV11
> doesn't. (Not sure why it even _has_ grant jumpers, given that one
> would usually make it the last card, especially since it has pull-ups
> - but I guess it's in case one doesn't.)
You can install it without the terminators
??? You'd have to desolder the terminator resistor packs (or do etch cuts),
no? It doesn't have any jumper/switch to disable them. (The Sigma backplane
has terminators in plug-in resistor packs, which can be removed.) The CD pinout is given in the 1980 Microcomputer
Interfaces Handbook under
the H9273-A entry (the H9276-A is the same; I forget where I found that one);
here it is:
Looking at the PMI pins in the KDJ11-B manual, it looks like there are
signal lines on the D2 pins for the memory. That's a +12v pin for
Qbus. The MSV11-J (PMI memory) manual confirms that that's exactly
what the problem is:
"NOTE: Insertion of the MSV11-J in a Q-Q backplane may damage other
components or the memory itself. The PMI bussing on the MSVI1-J's CD
connectors is not compatible with the +12 V bussing on the Q-Q backplane."
So it's the same problem as you would have with Unibus cards. That does
make compatibility a little easier.
- Dave