--- "Zane H. Healy" <healyzh_at_aracnet.com> wrote:
> > 1. Digital M7264
> PDP-11/03 processor
> > 2. H-11-5 Serial i/o
> > 3. H27 Floppy i/o
> > 4. H-11-5 Serial i/o
> > 5. M8044 CB
> 16 KW RAM
> > 6. M9400 YB
> 120-ohm Terminator
> > 7. WHA-11-16 16k x 16k Memory
> >
> >First question, does it matter how these boards are plugged into the
> >backplane?
To a certain extent - the CPU should be at one end of the Qbus, the M9400
at the other. Other stuff is not so critical.
> If so, where do they go? What are boards #6 and #7? The
The M9400 is at least a Qbus terminator if not a Qbus terminator and boot
card... I forget what the "YB" designator means, and my H-11 is not in
front of me (it has a KDF-11 "PDP-11/23+" CPU card in there, anyway).
The WHA-11-16 is some third-party card with which I am not familiar.
> Well, I would think that 6 & 7 are reversed, but I'm not familair with the
> H-11, so there might be soemthing wierd going on there.
It is wierd - the backplane is upsidedown - the cards go in with the solder
side up. It threw me for a loop the first time, too. Fortunately, I didn't
"fix" the problem and power up.
BTW, that 4x6 connector is Heathkit propietary. I have never seen one
anywhere else except hanging up on the wall of the local electronics
warehouse about 15 years ago back when that kind of connector was more
common. It's a type of Molex connector.
If you have _any_ DEC async boards, I'd pull the H-11-5 and go with a DLV11-J
or the like. I have an H-11-5. It's *not* in the H-11. It's on the shelf.
I do not have any docs, though, before you ask. I am stymied with the H-27
interface card. I have tested all the TTL ICs, but this thing still locks
up the Qbus when it's plugged into the grant chain with no gaps. With gaps,
it begins to read the floppy at boot time, but as soon as the boot code
turns on interrupts, because the interface is in the wrong place, the system
hangs, waiting for the interrupt that never comes.
I've been working on other systems recently - a pdp-8/e and pdp-8/L,
specifically.
-ethan
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Received on Thu Nov 18 1999 - 14:35:44 GMT