HP-85: Pictures of the PCB of the programmable ROM drawer

From: Vassilis Prevelakis <vp_at_mcs.drexel.edu>
Date: Thu Sep 25 09:24:46 2003

After popular demand :-) I am posting the URLs for said PCB:

Top View (with ICs):

Bottom view:

Installation Note for the programmable ROM drawer:

Notice the custom ICs between the TTL components and the bus.
Since the HP-85 bus uses 12V clocks and +6V logic, and that the
bus is bidirectional (thanks Tony), does anybody have suggestions
on how we can construct a replacement of the custom ICs?


Received on Thu Sep 25 2003 - 09:24:46 BST

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