This section provides the most common repair procedures for the 
  Enterprise 420R. The written procedures below are links to the 
Sun 
  Enterprise 420R Server Service Manual (806-1080). 
   
    | Component | 
     
       Remove 
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       Install 
     | 
    Tips | 
  
   
    | CD-ROM Drive | 
     
      
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      | 
  
   
    | CPU Module | 
     
      
     | 
     
      
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        -  
          
Tuning the ecache_scan_rate parameter of the Solaris 
            cache scrubber provides improved Ecache parity error protection on 
            non-mirrored SRAM UltraSPARC II-based systems (FIN  I0755-1).  
         
        -  
          
OS mapping versus physical location of CPU modules 
            for E420R, E450, U80 and Netra t1400/t1405 systems may lead to incorrect 
            module replacement (FIN  I0749-1).  
         
        -  
          
The current diagnostic procedure to 
            identify the faulty CPU module from CPU Ecache parity errors is flawed 
            (FIN I0570-3) 
         
       
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    |  
       Disk Drive 
     | 
     
      
     | 
     
      
     | 
      | 
  
   
    | Memory  | 
     
      
     | 
     
      
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      | 
  
   
    | Memory Riser Assembly | 
     
      
     | 
     
      
     | 
     
      
        - See 
 Memory Riser Assembly Damage 
          Caution. 
        - System initialization failures are sometimes being diagnosed incorrectly 
          due to an improperly installed Memory Riser card (FIN I0607-1).
 
        - Failure to properly assemble the Memory Riser to the correct torque 
          setting can cause intermittent memory related system problems (FIN I0537-2).
 
       
     | 
  
   
    | NVRAM/TOD Module | 
     
      
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    | PCI Card | 
     
      
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        - Ultra 80 system board based systems may panic at boot time with certain 
          PCI Bus configurations (FIN I0665-1).
 
        -  
          
 
            SunPCi II and SunPCi IIpro cards may not respond 
              after rapid/successive power cycling (FCO  A0186-1).  
           
         
        - Any PCI card may not seat properly and will cause the PCI card not 
          to be recognized by the system, rendering that PCI card inoperable (FCO 
          A0168-1).
 
        - A host system using the 375-0040-01 or -02 FC100/P FC-AL PCI card 
          to attach to FC-AL storage (StorEdge A5x00 and A3500) may experience 
          loop errors, which may affect data access to that storage (FCO A0164-1).
 
        - Systems based on the PSYCHO chipset panic with a PCI bus error (SRDB 
          40602). 
        
 
       
     | 
  
   
    | Power Distribution Board | 
     
      
     | 
     
      
     | 
      | 
  
   
    | Power Supply | 
     
      
     | 
     
      
     | 
     
      
        - Improper service procedures with the E220R/E420R power supplies could 
          result in system downtime. In addition, under certain circumstances, 
          the hot swapping functionality for the redundant power supplies may 
          fail (FIN I0666-1)
 
       
     | 
  
   
    | Removable Media Assembly (RMA) Backplane | 
     
      
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    | System Board | 
     
      
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    | Tape Drive | 
     
      
     | 
     
      
     | 
     
      
        - The peripheral D.C. power cable (530-2864-02) is too short to allow 
          the tape drive to be connected to D.C. power (FCO A0166-1).
 
       
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    |  
       UltraSCSI Backplane 
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