PAL on CDU-700 / 710 Unibus disk controllers

Ian Finder ian.finder at
Tue Apr 26 17:04:42 CDT 2016

The spec sheet from the PAL mfg. (signetics PLS173) seems to indicate
security fuses aren't an option on the model on my board. I have not
actually tried yet.

Failing that, if I can find one locally, there are only 12 bits of
combinatorial inputs.

I could easily whip up a little Arduino project on a breadboard to walk
thru all 4096 states and log the outputs for manual factoring.

- Ian

On Tue, Apr 26, 2016 at 3:00 PM, Glen Slick <glen.slick at> wrote:

> On Apr 26, 2016 2:35 PM, "Ian Finder" <ian.finder at> wrote:
> >
> > Does anyone out there have one of these controllers?
> >
> > There is an unprotected PAL- the address decoder- and I really need a
> dump of it. Many programmers, particularly the BP technologies ones, can
> read it
> Curious how you know it is not a protected PAL? The PALs are protected on
> all of the CMD CQD adapters I have looked at. I can't remember if I
> bothered checking the PAL on my CDU-720/M

   Ian Finder
   (206) 395-MIPS
   ian.finder at

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