Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!zodiac!joyce!sri-unix!garth!curry
From: curry@garth.UUCP (Ray Curry)
Newsgroups: comp.sys.mac
Subject: Re: $300 Mac II ADB fuse repair
Message-ID: <2494@garth.UUCP>
Date: 31 Jan 89 17:17:18 GMT
References: <11984@dartvax.Dartmouth.EDU> <76000341@p.cs.uiuc.edu>
Reply-To: curry@garth.UUCP (Ray Curry)
Organization: INTERGRAPH (APD) -- Palo Alto, CA
Lines: 16

In article <76000341@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
>
>Why does Apple do this sort of stuff?
>-- Why would anyone solder a fuse to a circuit board?
>-- Why would anyone solder a battery to a circuit board?

It's amazing how simplistic a view of the world we have.  Soldering in
fuses has been going on since fuses were invented.  You have them in your
stereo, tv, and lots of other places.  Some don't even look like fuses
but are avalance type diodes designed to open on failure.  The reason
for it is to protect against really bizarre circumstance that normally
won't happen.  There is no significant load that should be present on
the ADB bus and the fuse was probably added to protect circuitry in case
of abuse.  In such circumstances, where failure is 1 in a mil. or so,
the reliability of the soldered in is better.  Put it in a holder, you
have 1 failure in 100,000.  Solder it in and you have 1 in 1,000,000.