Further 11/40 unibus questions...

[Paul Anderson]

IS the 4 slot backplane a DD11-BF or a DD11-CF?  I don't think the M7891
will work in the -BF.

On Mon, Jun 1, 2009 at 9:56 PM, Paul Anderson <useddec at gmail.com> wrote:

> I always used a M930 in the 11/40 and older machines, and the M9300 in the
> 11/34 and newer machines. I have no way to check on the differences
> now. now.  Also, there may be a trick using MOS in an 11/40.
>
> Paul
>
>   On Mon, Jun 1, 2009 at 3:23 AM, Josh Dersch <derschjo at mail.msu.edu>wrote:
>
>>
>>
>> Henk Gooijen wrote:
>>
>>> Date: Sun, 31 May 2009 20:39:26 -0700
>>>> From: derschjo at mail.msu.edu
>>>> To:
>>>> Subject: Further 11/40 unibus questions...
>>>>
>>>> Hi all --
>>>>
>>>> Still having trouble with my 11/40, though it's getting closer.
>>>>
>>>> Currently the issue is:
>>>>
>>>> Without a unibus terminator installed, the machine seems to function in
>>>> that I can use the front panel, toggle in and run short programs, etc.
>>>>
>>>> With a unibus terminator installed, the front panel is _almost_
>>>> unresponsive -- I cannot examine or deposit memory or load addresses.
>>>> Toggling "Run" causes a brief flicker of activity (the "Run," "Proc,"
>>>> and "Bus" lights come on, the data lights flicker, and then they turn
>>>> off, and the "Console" light comes back on.).
>>>>
>>>> Ian lent me his M9300 terminator, which caused no changes in behavior.
>>>> So at least I can (probably) rule out a faulty terminator.
>>>>
>>>> I've verified that grant continuity cards (the tiny annoying ones) are
>>>> installed in slot D of all empty Unibus slots, and that the NPG jumper
>>>> is installed in all slots (since I currently have no DMA devices
>>>> installed).
>>>>
>>>> Question: Should the NPG jumper _also_ be installed in the one SPC
>>>> Unibus slot on the processor backplane? (I have a console SLU installed
>>>> there currently.) This does not currently appear to be present.
>>>>
>>>> Before I break out the logic analyzer this evening and start debugging
>>>> Unibus termination signals, I just wanted to make sure my current
>>>> configuration seems sane.
>>>>
>>>> The boards are installed as follows:
>>>>
>>>> Rear:
>>>>
>>>> Slot 4 : Empty M9300
>>>> Slot 3 : Empty
>>>> Slot 2 : M7891
>>>> Slot 1 : Empty | M981
>>>> ---
>>>> Slot 9 : M7856 | M981
>>>> Slots 1-8:
>>>> Front:
>>>>
>>>> (As mentioned before, all "empty" unibus slots have a unibus grant card
>>>> + NPG jumper installed, Slot 3 has the NPG jumper installed.)
>>>>
>>>> Thanks once again,
>>>> Josh
>>>>
>>>>
>>>
>>> The machine seems to do something (for a short while that is).
>>> The only thing I can say is what I have encountered. I was triggered
>>> when you wrote that you have the M7856 in slot 9 ... make sure that the
>>> CA1-CB1 (NPG) pins are wired together on the backplane!  The M7856 is
>>> one of the modules that does not use NPG, but also does NOT connect the
>>> two pins on the module! I have that written on my webpage www.pdp-11.nl
>>> (peripheral - comm - interface modules - DL11-W).
>>>  I remember that I soldered a wire on the module to connect those two
>>> pins,
>>> as I did not want to mess with the backplane ... If you do so, make sure
>>> that no flux and tin gets on the contact fingers!
>>>
>>> - Henk.
>>>
>>>
>>>
>> Thanks -- installed the NPG jumper for slot 9, no change.
>>
>> Here's a question:  The M9300 Ian lent me has three jumpers, labeled as
>> follows:
>>
>> W1 : "Remove jumper for beginning of non processor bus termination"
>> W2 : "Remove jumper for end of bus termination"
>> W3 : "Remove jumper for end of processor bus termination"
>>
>> Currently, W1 is installed, W2 and W3 are removed.  Is this correct?
>>
>> I'm curious what is meant by "processor bus" vs. just "bus" in this
>> context -- can someone fill me in?
>>
>> Thanks,
>> Josh
>>
>>
>