Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!mailrus!iuvax!purdue!decwrl!labrea!polya!rokicki
From: rokicki@polya.Stanford.EDU (Tomas G. Rokicki)
Newsgroups: comp.sys.amiga.tech
Subject: Re: My Lucas Board
Message-ID: <6324@polya.Stanford.EDU>
Date: 25 Jan 89 00:18:55 GMT
References: <9220@cit-vax.Caltech.Edu>
Organization: Stanford University
Lines: 12

> trouble with it.  On the replacable 7474 at U9, I am having the best luck
> with a 7474.  I havn't got a 74ALS74 to try yet, but the 74S74 and the 74LS74
> don't work most of the time.

Folks, these parts are *not* interchangeable, especially flip-flops!
I don't have my databooks around, but for some the combinations a
direct flip-flop to flip-flop won't work if they are of different
families because of the setup and hold vs. delay times!  Don't just
switch parts around like this unless you have your TTL data book and
a good timing diagram of the circuit you are messing with.  You're
just asking for intermittant failures.  Conservative design, folks,
conservative design.