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4.4.5
Power Supply Problems
Do not attempt to service the Power Supply Unit as opening or removing covers
may expose dangerous voltages or other hazards. Refer all servicing to service
personnel who have been authorized by Ericsson.
Use the following techniques to fault-find according to the observed symptom(s)
when a power supply failure is suspected.
4.4.6
Summary Status LED Unlit
If the Summary Status LED is unlit, fault-find as detailed in Table 4.1.
Table 4.1
Summary Status LED Unlit Fault-Finding
Step
Action
1
Check Status LED. Is the
unit still working?
2
Check Power Source.
Connect a known-working
piece of equipment to the
power source outlet. Does it
work?
Check Power Cable and
3
Fuse. Unplug the power
connector from the unit and
try it in another piece of
equipment. Does it work?
4
Check PSU Module(s) and
Fuse(s). Ensure the power
connector is unplugged.
Remove the fuse from the
rear panel connector and
inspect it. Has the fuse
blown?
4.4.7
Fan(s) Not Working/Overheating
The unit is fitted with fans, all of which run continuously. The unit contains a
temperature sensor that will highlight if there is a cooling problem. In the event of
overheating problems, fault find as detailed in
Table 4.2.
EN/LZT 790 0005 R7A
Warning!
If Result of Action is Yes...
If the unit is clearly working
normally then the Status LED
itself is probably at fault. Call a
Service Engineer.
The problem lies within the unit
or power cable. Proceed to next
step.
The problem lies within the unit.
Proceed to next step.
Replace the fuse with one of
the correct type and rating. If
the PSU still does not work,
unplug the power cable and call
a Service Engineer.
Preventive Maintenance and Fault-Finding
If Result of Action is No...
Proceed to next step.
The problem lies with the power
source. Check building circuit
breakers, fuse boxes, etc. If
problem persists, contact the
electricity supplier.
The problem lies with either the
cable itself, or with the fuse in
the plug. Replace the fuse or try
to substitute another cable.
Possible problem with the PSU
module. Call a Service
Engineer.
4-7
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