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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         :  ECD18014     DATE             : 93-06-17
 MANDATORY         :  N
 AUTOMATIC SHIPMENT:  N            SERVICE CODE     : 33
 PARTS SOURCE      :  YASU         AVAILABILITY DATE: 93/06
                                                                                
 PURPOSE:                                                                       

 To prevent memory error problems which may occur when Bus
 Master Adapter is installed in the PS/55 Model 5551-S Stage 2,
 and this Field EC was revised from EC# C80655 FBM# 79F5493.
 (Stage 2 machine has a white power switch lever)
                                                                                
 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/M54G1624 00.5 00.5 
   S09 B/M0005551    97XXXXA-->97XXXXB     B/M54G1624 00.5 00.5 
   S0A B/M0005551    97XXXXF               B/M54G1624 00.5 00.5 
   S19 B/M0005551    97AXXXX               B/M54G1642 00.5 00.5 
   S1A               97CXXXX                                    
                  (X IS ANY CHARACTER)                          

                                                                                
 PHYSICAL CHECK:                                                                

 Check the System Board P/N and EC#.                                            
 When the Bus Master Adapter is installed in the 5551-S Stage 2,                
 if the System Board is P/N 38F6769 and EC# C12859x or C80658x,                 
 install this FBM.                                                              
 (x means any Alpha/Numeric character)                                          
                                                                                
 PREREQUISITES: NONE                                                            
                                                                                
 COMPANION: NONE                                                                
                                                                                
 CONCURRENT: NONE                                                               
                                                                                
 DETAIL:                                                                        

 Replace the System Board with new part P/N 54G1611 .                           
                                                                                
 NOTES:                                                                         

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