1 Oct
2014
1 Oct
'14
7 a.m.
From: David Riley
Looking at the PMI pins in the KDJ11-B manual, it
looks like there are
signal lines on the D2 pins for the memory. That's a +12v pin for Qbus.
What I just cannot fathom is why they used D2! PMI is only like 14 signals or
so (plus normal QBUS signals like BDALxx), and there are heck of a lot more
than 14 available pins on the CD that _do not_ conflict with the normal QBUS
power, etc. (You lose xS1 and xB2, but the rest all look OK, although if you
want to stay away from +5 you lose a few more.)
Someone must have a bad case of brain fade, is all I can think.... But I'm
still pretty incredulous that nobody else caught it before it was too late.
Maybe it was deliberate - they hoped to increase sales through people burning
boards out, plugging them into the wrong backplanes? (Tongue 3/4 in
cheek... :-)
Noel