spiral formula?

Thank you for discussing this with me, and the information you have provided.

at

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there is a schematic of the tape interface electronics that are present on the CPU board in the Crusader II. This is PCB 483.

I have also traced where the lines go on the tape connector on the back of the machine (25 pin ?DB?) I will add a scan of that later today.

Thanks again !

Rich

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aiiadict
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I didn't have enough space on my site, so I created another one:

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Rich

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aiiadict

O.K. That explains why I could not get through to the first one.

Now *this* gives me a lot of hope. While it does not show the actual pinout at the DB-25 connector, what it *does* show is the numbers "89" and "88" in the drivers and receivers. Now -- back in those days, the most common RS-232 drivers and receivers were the 1489 and 1488. Some of them started with "MC", but other makers produced similar ones. All would have the 1488 and 1489 numbers in them. This increases the chances that this was a bit-banger interface emulating an RS-232, and can be used (with the proper AUX codes)

The chips are equivalent to the TI 75188 and 75189 -- one of each I see in the shaded out area, so that is probably what the "88" and "89" chips are. Anyway -- we are still talking about RS-232 drivers and receivers.

And even if the "data out" and "data in" pins don't wind up on pins 2 and 3 of the DB-25 connector, as long as one each of a 75188 and

75189 wind up on those pins, the software (selected by the AUX codes) can switch them around to be what you need.

Good Luck, DoN.

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DoN. Nichols

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Clark Magnuson

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I have posted a picture of the spiral I cut out in plywood using my Crusader II milling machine. Thanks alot to Fred!!

Rich

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aiiadict

Rich,

Thanks for posting the picture :-) Keep on making chips!

Fred

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ff

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