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AST RESEARCH, INC.          TECHNICAL BULLETIN # 1140               4-18-95

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				   BRAVO MS P/90 VIDEO SHADOW EFFECT


PROBLEM

The Bravo MS P/90 system may have a strong video "shadow effect".


CAUSE

The problem is caused by noise sensitivity of the feature connector from the 
Cirrus Logic 543x video chipset.  


SYSTEMS AFFECTED
AST PART NUMBER AND DESCRIPTION

501651-XXX          BRAVO MS P/90
501533-XXX          BRAVO MS P/60

SOLUTION

There are two solutions to the video "shadow effect":

1. Download the file 5434.ZIP from AST's BBS and unzip it.  
   At the DOS prompt, run 5434.COM to disable the driver circuits.  
   Type

	5434.COM

   anywhere in AUTOEXEC.BAT.  This will disable the feature connector.  
   For those user who need to use the feature connector, do not run this 
   program. 

File 5434.ZIP can be found on AST's BBS (817) 230-6850, in the "Systems" 
file area.  AST's BBS supports modem speeds up to 28.8k bps.
The above file will also be posted on: 

CompuServe 
Go ASTSUPPORT

AST Worldwide Web Site
http://www.ast.com

2. Run the program (5434.COM) with debug script at DOS prompt as follow:

Debug
A
MOV DX, 3C4
MOV AL, 18
OUT DX, AL
INC DX
MOV AL, C0
OUT DX, AL
MOV AH, 4C
INT 21

N 5434.COM
R CX
E
W
Q