Introduction and RK05J Drive cabling

Guy Sotomayor ggs at
Fri Jan 22 16:49:43 CST 2016

> On Jan 22, 2016, at 2:29 PM, tony duell <ard at> wrote:
> The M930 and BC11 should be easy to find, they are actually the same as the bits
> used on PDP11 Unibus connections.

I have had no end of problems with the *many* BC11A cables that I have (ie they’re
bad cables).  It’s the flex ribbon cable itself that’s been the issue.

To that end, I’ve made new “paddle” board that take 2 60pin ribbon cables.  I expect
to have the first round of boards back from the fab house in a couple of weeks.  I’ll
let folks know how they turn out (ie do they actually work!).

They differ from the DEC ones in a few of ways:
They’re full hight.  No more “knuckle” busters.
The cables are “standard” 60-pin ribbon (you need 2 ribbon cables)
The cables are not “fixed” to the paddle board but use 3M connectors for attachment
There are two versions of the paddle boards
normal “out the top”
90-degree right angle so you don’t have to “fold” the cables for certain uses (like RK05 drives)

I did these primarily because I need more cables and my BC11A’s are very flakey.  Also I have uses where I
need the cable to terminate to something that is agreeable to attach to other than another Unibus backplane.

The downside is that they were somewhat expensive (I ordered 10 of each just because that made sense price
wise for a prototype run).

TTFN - Guy

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