Power Supplies; Powering Down Dpp For Maintenance - Northern Telecom BCS35 Replacement Manual

Power supplies

Powering down DPP for maintenance

Powering down the DPP for maintenance is divided into two categories:
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•
xs
+8.5 V dc power down, removal, or maintenance of circuit packs requires
removing the +8.5 V dc output from the DPP power supply. The circuit
breaker is a push ON (1), push OFF (O) rocker switch. Press the rocker
switch to the OFF (O) position to manually open the +8.5 V dc line. To
reset an automatically tripped circuit breaker, first push the OFF (O) side of
the circuit breaker, then push the ON (1) side.
–48 V dc Power Down. Power down the –48 V dc C.O. input power for
maintenance on the following:
•
•
Since the processor and disk in the chassis are powered down, make sure the
processor mode and the disk mode are ONLY (toward the other chassis and
disk) before the power is removed.
When performing any type of maintenance on the fan (fan not running),
open the front cover of the DPP to improve convection cooling. Perform the
necessary functions. Power down the –48 V dc when the fan is inoperable
for extended periods of time to prevent damage from overheating.
For maintenance, power down the –48 V dc at the external circuit breakers
(or other disconnects) for power distribution control. Note the location of
the disconnects before removing any equipment in case of an emergency.
Only remove the –48 V dc fuse from the power supply to power down the
DPP in an emergency.
Leave the disk drives untouched for at least 30 seconds after power down
since vibration during power down may damage the disk drive.
+8.5 V dc power down
–48 V dc power down
Power supply
Cooling fan (except for brief periods of time, i.e. when the required
spare parts are near at hand).
DPP Card Replacement Guide BCS35 and up
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