Further 11/40 unibus questions...

[Josh Dersch]

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

It's a DD11-C backplane.  The memory appears to work fine (I did some 
basic testing of it from the front panel w/out the terminator installed.)

Thanks,
Josh

> 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:
>>
>>
>>     
>>>> 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
>>>
>>>
>>>       
>
>
>