AST RESEARCH, INC.        TECHNICAL BULLETIN # 1722          05/20/97 
 
 
 
TITLE:  RF Gasket Installation Precautions
 
 
ISSUE 
 
   When installing a third-party peripheral device into one of the 
   external drive bays, the device's circuit board may be shorted 
   out if the installer is not careful when attaching the RF gasket 
   to the device. This could result in damage to the device or the 
   computer.
   
   Some peripherals examined have little or no clearance between the 
   device's circuit board and the top or bottom edges of its frame. 
   
   This issue applies to any system shipped with accessory RF 
   gaskets.    

 
BACKGROUND 
 
   It is sometimes necessary to attach conductive RF gaskets to 
   devices when installing them into external drive bays on some 
   systems.  RF gaskets ensure Electro-Magnetic Interference (EMI) 
   does not exceed acceptable levels for the FCC-type acceptance for 
   that particular system. 
   
   AST ships the necessary RF gaskets for systems requiring them in 
   the accessory kit included with that system.    

 
ACTION 
 
   To ensure that the circuit board will not short out, follow the 
   procedure outlined below. 
   
   NOTE: Perform this procedure BEFORE applying power to          
   the system to avoid equipment damage.
   
   Carefully inspect for sufficient clearance between the RF gasket 
   and the device's circuit board, after installing it into the 
   external drive bay. It is important to perform this visual 
   inspection after installing the device into the computer. 
   Adjacent devices and blank filler panels will tend to compress 
   the gasket down onto the device.
   
   If a clearance issue is detected (or suspected), the installer is 
   responsible for ensuring that the device's electronics are 
   properly insulated from the gasket.    

 
NOTES 
 
   Failure to follow this procedure may void your system's warranty.    

 
TAN TPR 2032MH 
 
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