MAINTENANCE
Removing and Restoring Power
When the following procedures are performed, the system must be unplugged from the ac power source:
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Reseating or replacing the Service Circuit or CPU/Memory CPs
Replacing the frontplane
Processor and Memory CPs (Release 1 only)
●Replacing the power supply
●Replacing the fan assembly.
Danger: The System 25 cabinet(s) contain hazardous voltages. This equipment must be serviced only by qualified
technicians.
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Before removing power from one or more cabinets, save translations on the tape backup. To save translations, follow the procedures under “Using the Digital Tape Unit” in this section.
To remove power from a cabinet, set the power switch on the rear panel of the cabinet to the OFF (0) position. Unplug the cabinet power cord. When the repair or replacement has been completed, restore power by plugging in the cabinet power cord and setting the power switch to the ON (1) position. Note that when power is removed from the first cabinet (contains the common control circuits), the Emergency Transfer Unit automatically activates.
CAUTION: Removing a CP that is in use will cause users to be disconnected.
