DEC MKA11 and/or M8261/M8163

Eric Smith spacewar at
Mon Feb 16 02:27:07 CST 2015

On Mon, Feb 16, 2015 at 1:05 AM, Paul Birkel <pbirkel at> wrote:
> Notice the two unused connectors on the M8162 there in the middle slot
> (#15).
> As this looks like an operational configuration, I infer that those two
> connectors are used for ... nothing?  Test points (through series
> resistors)?
> I see (how can one miss!) the address and data ribbon-cables.  The
> remaining white ribbon-cables must be for the box controllers. So, that
> looks like a 1Mw configuration.  Maybe 1.5Mw if, as you suggest, you're
> careful?

It appears to me that the off-white or light-grey cables are address
and data cables, just as the grey ones, and the color was simply what
was available at the time, or from a different cable vendor. The other
boxes show different mixes of shades of gray for their cables.

I believe that the molex connectors on the card in slot 15 are for the
control box, and were either removed for the photograph, or were not
necessary for the operation of the machine.  Note that CPU A and B do
not have fully populated memory control panels, which suggests that
the memory control panel wasn't strictly necessary for machine
operation, though obviously very desirable for diagnostic purposes.  I
don't really know, but if I'd designed the MKA11, I would have
designed it so that without the controller connected, all ports are

More information about the cctech mailing list