450 activity led blinks on one system and is steady on another...why
does that occur?                              

From FIN I0406-1

Some confusion has been noted in the field in reference to the front 
panel status LEDs on Ultra 450 Workstations and Ultra Enterprise 450
Workgroup Servers, that blink on some systems and not on others.

The following is an explanation of the apparent random front panel LED
activity:

The Ultra Enterprise 450 and Ultra 450 NVRAM variable mfg-options sets
the system up as a workstation or server.  The system name displayed in
the banner, energystar, watchdog-enable, and the front panel LEDs are
controlled by this variable.

Set the mfg-options NVRAM variable to the correct system type relative
to the desired led-blink status.
 

1. The front panel status LEDs will blink if the mfg-options NVRAM  
    variable is set to 49.

        Workgroup Server setup:
        OK> setenv mfg-options 49 

        banner          Ultra Enterprise 450
        energystar      disabled
        watchdog        enabled
        led-blink       enabled         


2. The front panel status LEDs will NOT blink if the mfg-options  
    NVRAM variable is set to 0.

        Workstation setup:
        OK> setenv mfg-options 0

        banner          Ultra 450
        energystar      enabled
        watchdog        disabled
        led-blink       disabled

     On newer E450's with a system board part number of 501-5270,
501-5672 or 501-5673 the following is true if OBP is 3.12.3 or greater.

    For the front panel LED to blink the "mfg-options" must
be set to "server" Ex. OK> setenv mfg-options server

    For the front panel to remain steady the "mfg-options" must
be set to workstation. Ex. OK> setenv mfg-options workstation.

    Failure to do so will result in the message "WARNING
mfg-options environment variable invalid".