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Everex EV-170 / 170A Magic IO Board revision?

C

clh333

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In another thread I have described my efforts to restore an IBM PC XT. In terms of IO I have one LPT (a port on the video card) and one COM, a port on the 1200 baud modem. I now want to install an Everex "Magic I/O Card" which features extra serial and parallel ports.

Depending on the model purchased this card came with an optional clock. Because I originally purchased the board to use with an AT&T PC6300, and the 6300 had a built-in clock, I omitted this option. I think mine therefore is a 107A.

Now I am wondering if a clock chip could be retrofitted. I have the original manual and software that came with my board, but no reference to guide me as to what is missing or where it was installed (except for the obvious coin battery)

Does anyone have one of the boards with these extra components? A photo of the front side of the board would help me judge the degree of difficulty of this modification. Alternately, if you have a spare one you want to get rid of, let me know.

Thanks for your replies.

-CH-
 
If you mean the EV-170A... it's for an AT and therefore doesn't have the clock.

I have one, NIB, and the models EV-170 and EV-170C have the clock.

If anyone wants the NIB, EV-170A, it's available.
 
Yes, I mean 170A. #*%^%$ dyslexia.

If I get another board it has to fit the XT bus, have a clock, battery and one serial port to drive the plotter; the rest is gravy. I believe that clock chip was a National Semiconductor MM58167A, which apparently was used in the AT on-board. They're around but pricey. From a Ciarcia article of the period I gather there were more components necessary to complete the function.

I know there were four models of the EV-170 but I don't recall what were the differences. But I do recall only two had the clock. If you say 170 and 170C, who am I to argue?

Thanks,

-CH-
 
Found a solution in an inexpensive DTK ISA RTC card, purchased on eBay. Used the MZD DTK driver. Works.

Now one question remains: Can I use the Everex 170 in Slot 8 (closest to the Power Supply)?

I know IBM warns that the wiring is different for that slot, as it was intended for <something esoteric> but the 170 documentation says you can use the card in the slot if you jumper "cs" which is a header near the bottom of the card. It would be ideal if I could use that slot for something as the card is short and real estate is getting scarce.

What's the penalty for being wrong on this? Any thoughts?

-CH-
 
There's no penalty -- either it works or it doesn't. :)

I think cards that are designed (wired) for slot 8 are the only ones you can get to work in it and if it's thusly documented, go for it.
 
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