Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!ames!ncar!tank!uxc!uxc.cso.uiuc.edu!uxd.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.sys.ibm.pc
Subject: Re: System Unit Design
Message-ID: <45900213@uxe.cso.uiuc.edu>
Date: 19 Mar 89 15:21:00 GMT
References: <1256@wpi.wpi.edu>
Lines: 21
Nf-ID: #R:wpi.wpi.edu:1256:uxe.cso.uiuc.edu:45900213:000:971
Nf-From: uxe.cso.uiuc.edu!mcdonald    Mar 19 09:21:00 1989



<long description of what it took to replace the power supply fuse deleted>

>	Why would a designer place a disposable/exchangable part
>     (such as a fuse) deep inside a 'sealed' assembly that has
>     existing external connections?  

To increase service revenue, that's why. I keep a log of repairs to the
equipment in my lab ( a couple million bucks of lasers, computers, 
electronics (and low tech (yuck) vacuum pumps).) We have found ,
over the years, that 50% of fuses that blow, do so for no reason we
can find - no broken parts, no short circuits, no dead cockroaches
or mice in sight (this latter is not a minor problem due the fact
that the wonderful state of Illinois has us in a building built in 1900).
Replace the fuse and the object works fine for another year.

So I am very leary of any claims that "this fuse can't blow unless
something else inside the power supply dies first".

Intentionally breakable parts like fuses should be user replacable.