In a message dated 12/13/2006 2:01:54 P.M. Eastern Standard Time,  
[log in to unmask] writes:

have two  membrane keypads that have shown intermittent "short circuit"  
failures. 
Hello, Carl:
 
OK, you've probably already looked for residual conductive ink between  
conductors, but look closer for dust. Over-cured thick film conductive  polymers 
lose ductility and become [relatively] brittle. The "...wiggling,  banging..." 
you described could produce enough conductive particulate between  the circuits 
to yield an intermittent high-resistance short.
 
I'm also wondering about your dielectric: What is the dielectric  material 
(e.g., is it solder mask)?
 
 
ROBERT LAZZARA
VP, Business Development
T: (800) 560-9457
F:  (800) 878-5566 (y servicio de mensaje español)
E:  [log in to unmask]
W:_  www.CircuitConnectUSA.com_ (http://www.CircuitConnectUSA.com) 

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