Date   : Sat, 02 Jun 1984 07:08:00 MDT (Sat)
From   : Keith Petersen <W8SDZ@Simtel20.ARPA>
Subject: Apple ALS CP/M card 74S109 vs 74F109

Date: Fri, 1 Jun 84 11:32:05 EDT
From: James Byrd <jbyrd@BBN-VAX.ARPA>
Subject: 74S109 vs 74F109
To: info-apple@BRL-AOS.ARPA

A friend of mine (not on the net) tells me a curious story:  He was having
problems with his ALS CP/M card occasionally freezing.  He called ALS, and
they told him to look in location C1 of his Apple IIe and see what chip was
there.  According to the Apple specs, it should be a 74S109, but sometimes
Apple uses a 74F109.  Some subtle difference between the two causes the
problem, and putting in a 74S109 solves it.

Has anybody else run into this?  I'm not an engineer, so I don't really
appreciate the differences between the various flavors of 74x109.

Jim Byrd