On 24.05.2016 16:25, David Collins wrote:
  Here are the binaries for all the EPROMs on processor
PCA for my 7596A. 
Wow, that was really quick, thank you so much!
  The
 PCA part number is 07595-60100 and is different from the one in the manual
 which is a 07595-60200 so I assume my PCA is older than the one in the
 manual. 
Judging by your photos and the ones I made last time I had the plotter
open, I'm pretty sure that's the same PCA ours has.
  07595-18097     U28
 07595-18098    U37 
Our plotter only had these two sockets populated. The two ROMs contain
the even/odd bytes of a 128K image. I combined them and compared them to
the dump we took of our broken ROMs (with lots of bit errors), and they
seem to be structured very similarly, so this might well be a later
version of the same firmware.
  Unknown U27 - no part number label
 Unknown        U36 - no part number label 
These are mostly empty and I couldn't find any recognizable strings in
there. Might be additional machine code as the U28/U37 ROMs are pretty
chock full.
The 17225-* ROMs don't look like firmware, but seem to contain several
demo plots, maybe for exhibition purposes?
  Binaries for each chip are attached. All are 27512
EPROMs. 
Nice, we even have a few of those in our parts collection \o/ I hope
I'll find time this weekend to burn and plug them and give them a test run.
  I have also included photos of the PCA and the EPROMs
in position.  Hope
 that helps. 
Yes, very much, thanks again!
All the best
   Joachim