HP Draftmaster II 7596A: EPROM dumps needed, urgent :-(

[Ethan Dicks]

On Sun, May 22, 2016 at 3:51 PM, John Robertson <jrr at flippers.com> wrote:
> On 05/21/2016 10:53 PM, David Collins wrote:
>>
>> Martin, I might be able to help you as I think we have a 7596A...
>>
>> I haven't looked at the plotter itself, but the service manual we have
>> shows the following part numbers for the processor PCA
>>
>> 07595-18039
>> 07595-18040
>> 07595-18041
>> 07595-18042

After wrestling it out of a tight corner and pulling the side panel
off and all the machine screws and nuts off the electronics housing,
my 7596A had 2 EPROMs, marked (w/Intel logo):

  1818-3825
  S70137

According to http://www.cpu-world.com/forum/viewtopic.php?t=25006,
they should be 27C512s.  They are 28-pin parts with the same
coloration and lettering as real Intel 27C512s.

>> the EPROMs are labeled 07595-18045 and 07595-18046.

The paper labels on mine have the part numbers:
 07595-18095
 07595-18096

Could you have read '4' instead of '9' perhaps, or perhaps mine are a
different revision?

My plotter has two DB25F connectors and one IEEE-488 connector.  I'm
not sure what other features (besides date of manufacture) might lead
to different ROM revisions.

> If your version has four EPROMs and the later (otherwise identical) machine
> only used two then chances are the four earlier EPROMs were simply combined
> into two later ones. For example, if the original EPROMs were 2708s then two
> of those would fit into a single 2716. The 2716 was easier to program as
> well being only a single voltage device.

This device is far newer than those parts, but the principle is the
same, of course.

I should be able to read these out this week and share the contents.

-ethan