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From: fish@ihu1g.UUCP (Bob Fishell)
Newsgroups: net.audio
Subject: A CD anecdote: keep it clean!
Message-ID: <322@ihu1g.UUCP>
Date: Thu, 3-May-84 16:10:41 EDT
Article-I.D.: ihu1g.322
Posted: Thu May  3 16:10:41 1984
Date-Received: Fri, 4-May-84 07:23:50 EDT
Organization: AT&T Bell Labs, Naperville, IL
Lines: 31

(oo)
Having seen a recent group of articles about cleaning CDs on the
net, I began to wonder just how critical this was.  I had replied
that a CD should be treated like a good camera lens, i.e., keep
fingerprints and dust off.

Anyway, I thought I'd try an experiment.  I took out my least-favored
CD and proceeded to place a large, very greasy thumbprint across the
playing surface.  I did this by immersing my thumb in sausage grease
left over from dinner and wiping off just the excess, so you can imagine
what this print was like.  I tried to play the disc in my Technics PL-7,
and got silence.  Apparently, I had messed up the surface enough to 
completely shut down the error correction circuitry.

I removed the disc and cleaned it with the same lens cleaning solution
I use on my eyeglasses.  The enormous print gone, the disc played
perfectly clear through.  Repeating the experiment with a normal,
body-oil fingerprint, the error correction circuit had no problem
this time, and the disc still played perfectly.

Moral: error correction is good, but not magic.  Try to keep the 
disc clean!  I think that scratches are probably the most harmful
thing you can get on a CD, but I was not about to try it.  I don't
disfavor my test disc THAT much.

To Phil R. and the rest of the anti-CD crowd: try this experiment with
an analog disc and post the results to the net... :-)
-- 

                               Bob Fishell
                               ihnp4!ihu1g!fish