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Re: Saturn 128k Problems

On Tue, 5 Jun 2012, Steven Hirsch wrote:


On 06/04/2012 10:49 AM, Hugh Hood wrote:

Steve:

I booted up RoboCAD on my IIe this morning and tested:

A. Ctrl-Reset -> RoboCAD 'traps' the reset key and presents a message about
'Press Return to Continue'

This keeps you from losing your drawing and keeps (most) folks out of the
monitor for disassembly

B. OA-Ctrl-Reset -> the machine reboots


This is in a machine with a Transwarp (with the Saturn card selection), so
throw that variable into my test results.
I cannot reproduce that, leading me to believe that I do have a problem with the Saturn board. I'm going to try swapping out some of the LS TTL logic for newer parts and see if I can get it to behave. 

Would still be great if someone had the schematic.
I recall that it used that pair of Motorola ICs designed for controlling dynamic ram, one is a multiplexer the other is a controller. Large multipin ICs, and they should jump out when you look at the board. There should be a datasheet or application note devoted to those ICs, and I suspect the board can't be much different from that "typical design". That would make a good start to a schematic, the interface to the bus can't be too complicated. 

   Michael