Sun Enterprise 6500/5500/4500 Systems Reference Manual

No AC or DC Power

Table 10-1 AC/DC Power Problems




No AC 

Fans are not turning 

No LEDs 

Check incoming AC power.  



Check keyswitch setting.  

See "Restarting the System".

Check AC distribution unit switch 


See Figure 11-2.

No DC or yellow LED is lighted 


Check system front panel LEDs or clock+ board LEDs. 


See Table 9-1.


Check PCMs. 


See Table 9-2, Table 9-3.


Check peripheral power supply.  




Check CPU/Memory+ boards.  




If clock+ board is faulty, system operation/diagnostics may be erratic. 



System error messages 


Check LEDs on: --Front panel --Clock+ board --Peripheral power supply --PCMs --CPU/Memory+ boards --I/O+ boards  

See Chapter 9, Troubleshooting Overview.