[urq] urg computer question

[Steve Eiche]

Anton,
There are actually three different variations of the MAC-02 PCA.  The "RDH" schematic is based on a revision of the version 1 PCA. There is a local gentleman that has a copy of the actual schematic for some version of the MAC-02 from Hitachi, but I have yet to arrange getting a copy of it from him, although he has offered. The circuitry itself is pretty basic, so I usually don't even bother with the schematic. FWIW, the major components on the PCA have been NLA for over a decade, with little or no documentation as to their exact function or specs.  

I know where you are going with this, but personally I think that the best solution would be to make a replacement PCA that could run improved code with modern components.  I don't see any reason to duplicate what is a poor design to begin with.  While I was at it, I would fix design issues like the stupid low resistance intake air temp sensor and replace the MAP sensor with a modern Motorola part, etc.  You might as well add some rudimentary diagnostics and external programming while you are at it. Maybe that is what you have in mind.  I do believe that the main connector is still available from AMP.  

As to the mechanical specs for a CAD, you might as well make those yourself.  That's easy. I doubt Hitachi even has those anymore.

Steve 



One page schematic. I was expecting more. Now I need a parts list to source parts and a mechanical drawing for the board outline, keepout areas, mounting and tooling holes. Fixed components like connectors would be a must as well.

... I suppose you all see where I'm going with this.