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                           IBM ECA
              Engineering Change Announcement

Parts removed from this machine and returned to IBM must be genuine,
                      unaltered IBM Parts

         IBM World Trade Corporation, CE Department Germany
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 EC NUMBER         :  ECC27278     DATE             : 91-07-04
 MANDATORY         :  N                               93-06-17
 AUTOMATIC SHIPMENT:  N            SERVICE CODE     : 33
 PARTS SOURCE      :  FUJI         AVAILABILITY DATE: 90/02
                                                                                
 PURPOSE:                                                                       
 TO PREVENT HUNG-UP PROBLEM WHICH MAY OCCUR WHEN A ADAPTER WHICH                
 HAS BUS MASTER FUNTION IS INSTALLED AS AN OPTION IN THE SYSTEM                 
 UNIT.                                                                          
 THE SCSI ADAPTER AND NUMERIC PROCESSING ADAPTER HAVE BUS MASTER                
 FUNCTION.                                                                      
                                                                                

 Type             Machines Affected                             
 Mod.  With       and/or Feature/Device    B/M to be  Serv Syst 
 Stg.  B/M        Description              Installed  Hour Hour 

 Plant 97                                                       

 5551  B/MBASIC   9700001 THRU 9719300     B/M64F8690 00.8 00.8 
   S09 B/MBASIC   9730001 THRU 9744700     B/M64F8691 00.8 00.8 
   T09 B/MBASIC   9760001 THRU 9775800     B/M64F8692 00.8 00.8 
   T0A B/MBASIC   9790001 THRU 9793100     B/M64F8692 00.8 00.8 
   T0B                                                          

                                                                                
 PHYSICAL CHECK: NONE                                                           
                                                                                
 PREREQUISITES: NONE                                                            
                                                                                
 COMPANION: NONE                                                                
                                                                                
 CONCURRENT: NONE                                                               
                                                                                
 DETAIL:                                                                        
 REPLACE THE SYSTEM BOARD IN THE SYSTEM UNIT AND PERFORM THE
 TEST ONE OF THE FOLLOWING SYSTEM BOARDS IS INCLUDED IN THIS
 FBM.
                                                                                
    FBM# 64F8690: 5551-S09 SYSTEM BOARD(16MHZ)     P/N 56F7422                  
    FBM# 64F8691: 5551-T09 SYSTEM BOARD(20MHZ)     P/N 56F7421                  
    FBM# 64F8692: 5551-T0A/T0B SYSTEM BOARD(20MHZ) P/N 56F7415                  
                                                                                
 NOTES: THE FBM IS AVAILABLE FOR ONE YEAR.                                      
 REMOVED OLD SYSTEM BOARD MUST BE RETURNED WITH EC COMPLETION                   
 REPORT TO STOCK CENTER AS SOON AS POSSIBLE AFTER EC INSTALLED.                 
 ---->REVISED                                                                   
 APPLICABLE PERIODE OF THIS FBM WAS EXPANDED UNTIL THE END OF                   
 FEBRUARY IN 1992.                                                              
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