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From: griffin@frith.uucp (Danny Griffin)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Can I replace a MC74F139 IC with a 74LS139 IC??
Message-ID: <1991Mar11.063722.16378@msuinfo.cl.msu.edu>
Date: 11 Mar 91 06:37:22 GMT
References: <1991Mar10.184945.14146@engin.umich.edu> <1991Mar10.185521.14238@engin.umich.edu>
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chymes@zug.csmil.umich.edu (Charles Hymes) writes:

>The PD I/O expantion board I just built dosent work, and the current
>thing to try is to replace the chips. The board uses a R65C22p1 CMOS
>VIA a R65c52p1 CMOS DCIA and a MC4F139 IC.
>Ive gotton ahold of a number of 74LS139 chips, and I'm going to replace
>the MC74F139 with it. The difference being LS vs F.  I think LS means
>low power Shottsky, but what does F mean, and can I interchange the
>chips? Does this make them incompatable?


F means Fast.  Whether or not it makes a difference in this application
I don't know, but I would suspect so or it wouldn't have been spec'ed.

I also built the PD I/O and had some problems.  If you are having problems
with the serial port, (like with different parities not working) make sure
you get the new newser.device.  If you are having problems with the
parallel ports, it is something you did.  After building the board, nothing
worked at first (at leat the way I wanted it to) :-) but now all the new
ports work fine.


--
Dan Griffin
griffin@frith.egr.msu.edu