Lenovo ThinkServer RD120 Hardware Maintenance Manual page 203

v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 3, "Parts listing, ThinkServer RD120 Machine Types 6444, 6445, 6446, and 6447," on page 25
to determine which components are customer replaceable units (CRU) and which components are field
replaceable units (FRU).
v If an action step is preceded by "(Trained service technician only)," that step must be performed only by a
trained service technician.
System event/error log message
+12v critical over voltage fault
+12v critical under voltage fault
Action
1. If the OVER SPEC LED on the Easy LED Diagnostics panel is
lit, or any of the four power channel error LEDs (A, B, C, or D)
on the system board are lit, see the entries about
power-channel error LEDs in "Power problems" on page 155.
(See "Internal connectors, LEDs, and jumpers" on page 8 for
the location of the power channel error LEDs.)
2. If the actions in "Power problems" on page 155 do not identify
a defective component, complete the following steps:
a. Remove the power supplies.
Attention: In a dc power environment, only trained
service personnel other than Lenovo service technicians
are authorized to connect or disconnect power to the dc
power supply and to install and remove the dc power
supply. See the documentation that comes with each dc
power supply.
b. Replace the power supplies one at a time, restarting the
server each time, to isolate a failing power supply.
c. If the server fails to start, replace the power backplane.
Restart the server.
d. If the server fails to start, (trained service technician only)
replace the system board.
1. If the OVER SPEC LED on the Easy LED Diagnostics panel is
lit, or any of the four power channel error LEDs (A, B, C, or D)
on the system board are lit, see the entries about
power-channel error LEDs in "Power problems" on page 155.
(See "Internal connectors, LEDs, and jumpers" on page 8 for
the location of the power channel error LEDs.)
2. If the actions in "Power problems" on page 155 do not identify
a defective component, complete the following steps:
a. Remove the power supplies.
Attention: In a dc power environment, only trained
service personnel other than Lenovo service technicians
are authorized to connect or disconnect power to the dc
power supply and to install and remove the dc power
supply. See the documentation that comes with each dc
power supply.
b. Replace the power supplies one at a time, restarting the
server each time, to isolate a failing power supply.
c. If the server fails to start, replace the power backplane.
Restart the server.
d. If the server fails to start, (trained service technician only)
replace the system board.
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Chapter 5. Diagnostics