Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!rochester!pt.cs.cmu.edu!cive.ri.cmu.edu!mack
From: mack@cive.ri.cmu.edu (Clark McDonald)
Newsgroups: sci.electronics
Subject: Re: Mechanical Light Timer Problem
Message-ID: <5137@pt.cs.cmu.edu>
Date: 6 Jun 89 22:22:26 GMT
References: <40651@bbn.COM>
Distribution: na
Organization: Carnegie-Mellon University, CS/RI
Lines: 35


>From: gonzalez@bbn.com (Jim Gonzalez)
>Path: bbn.com!gonzale
>Is it possible that the mechanical timer is causing damage to the
>lamp switches?  Could a bouncy timer switch generate impulses that
>would damage the contacts in the lamp switch?  Has anyone else had
>this problem?
>
>				-Jim.
>
>----------------------------------------------------------------------
>Jim Gonzalez				AT&T: 617-873-2937
>BBN Systems and Technologies Corp. 	ARPA: gonzalez@bbn.com
>Cambridge, Massachusetts		UUCP: ...seismo!bbn!gonzalez
>----------------------------------------------------------------------

I think that the problem lies in the fact that the switch located on the 
lamps was left in one position too long.  Those switches are usually 
designed to be self-cleaning when operated.  If the contacts are left 
in the closed (or open) position for extended periods, the wiping action 
produced when turning the switch is defeated.  Corrosion, cigarette smoke 
(a biggie in home audio switches), forced-air heating/cooling systems and 
the like do big damage to plated contacts over time.  Every once in a while, 
you should OPERATE the switch of the lamp to clean it.  If not, you will 
end up with the troubles you describe, which get worse and worse steadily with 
time.  Once an AC power switch starts this behavior, I have never seen one 
that could be brought "back to life" with cleaning agents, etc.  The cure 
is to replace the switch.  Then, USE IT every once in a while.  An 
alternative would be to simply throw the switch several times with 
the power OFF to initiate the wiping action described above.  

Disclaimer:   Disclaimer?  I don't even know 'er.  But BE CAREFUL if 
you are replacing the switch yo' sef.

 
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