Technical data

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Chapter 7: Using the System Controller
Understanding the MSC LEDs and Switches
The System Controller has one keyswitch, two push buttons, and four LED indicators.
The following paragraphs provide information on the use or significance of each control
or indicator.
The Front Panel Keyswitch selects Standby, On, or Diagnostic status for the system.
The System Reset push button initiates a system-wide reset of the deskside. The
keyswitch must be in the diagnostic position to use this button.
The Non-Maskable Interrupt (NMI) switch issues a reset signal to all Node boards in the
system. The keyswitch must be in the diagnostic position to use this button.
The AC Power OK green LED lights when the system is plugged into an outlet and the AC
circuit breaker is turned on. The Controller is receiving DC voltage (V_5 Aux) through
the midplane, as are other boards that require it.
The DC Power OK green LED lights three and one-half seconds after the keyswitch is
turned to the On position. This indicates the system power supply is enabled and
operating properly.
The Fan Speed High amber warning LED lights when the fans are running at high speed,
which may be an indication that ambient temperature is higher than optimal or a
non-critical fan has failed. When a non-critical fan fails, the remaining fans are set at full
speed to compensate. In this case, a service call should be placed immediately.
The Over Temperature Fault amber warning LED lights when the controller’s incoming
air temperature or fan failure detection causes a shutdown of the system. If the
environmental temperature exceeds the system’s tolerance, or if a critical fan fails, the
controller shuts down the system. In some cases, a service call should be placed
immediately. See the section “MSC Shutdown” in Chapter 8 for tips on how to
troubleshoot this problem area.