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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         :  ECD22612     DATE             : 93-06-17
 MANDATORY         :  N
 AUTOMATIC SHIPMENT:  N            SERVICE CODE     : 33
 PARTS SOURCE      :  YASU         AVAILABILITY DATE: 93/05
                                                                                
 PURPOSE:                                                                       

 To solve hung-up problems which may occur when the Bus Master                  
 Adapter is installed in the PS/55 Model 5551-T Stage 1 ,and                    
 this field EC was revised from EC# C27278 FBM# 64F8962.                        
                                                                                
 The following adapters have Bus Master Function.                               
 -Micro Channel SCSI Adapter/A (16Bit,32Bit)                                    
 -Inteligent Communication Adapter/A Portmaster                                 
 -Numeric Processing Adapter                                                    
 -Japanese Voice Adapter/A                                                      
 -80MB HDD attached SCSI Adapter/A                                              
 -Token Ring 16/4 Bus-master 32 Adapter/A                                       
                                                                                

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

 Plant 98                                                       

 5551- B/M0005551 S/N RANGE                B/M64F8692 00.5 00.5 
   T0A B/M0005551    9770001-->9775800     B/M64F8692 00.5 00.5 
   T0B               9790001-->9793100                          

                                                                                
 PHYSICAL CHECK:                                                                

 Check the System Board P/N.                                                    
 When the Bus Master Adapter is installed in 5551-T0A/T0B Stage
 1 if the System Board is P/N 94X1572, install this FBM.
                                                                                
 PREREQUISITES: NONE                                                            
                                                                                
 COMPANION: NONE                                                                
                                                                                
 CONCURRENT: NONE                                                               
                                                                                
 DETAIL:                                                                        

 Replace the System Board with P/N 56F7415                                      
                                                                                
 NOTES:                                                                         

 Return the removed System Board with EC completion report                      
 to stock center as soon as possible after EC installation.
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