Troubleshooting guide

2. Troubleshooting Switch Failures
17
Table 2-2: Points to be checked in case of power failures
6 The STATUS LED of the BCU, CSU, or MSU
is lit in red, the other LEDs are all off, and no
message is displayed on the system operation
panel.
1. Check the single or redundant configuration of the BCU,
CSU, or MSU modules.
(1) When a single configuration is used, follow steps 3
onwards shown below.
(2) When a redundant configuration is used, follow steps 2
onwards shown below.
2. Check the status of the active and standby BCU, CSU, or
MSU modules.
(1) If a fault only occurs on one of the units, replace the
applicable BCU, CSU, or MSU. In this case, you do not
need to perform steps 3 onwards shown below.
(2) When both active and standby systems have failed,
follow steps 3 onwards shown below.
3. Check the power supply unit LEDs.
(1) If the ALARM LED of any power supply unit is lit in
red, replace the power supply unit.
(2) If both the POWER LED and ALARM LED of any
power supply unit are off, follow the procedure shown in
Table 2-2: Points to be checked in case of power failures.
If the problem persists, replace the power supply unit
whose LEDs are off.
(3) If all the power supply units are operating properly,
retain them as they are.
4. Turn off all the power supply units implemented on the
Switch.
5. Wait at least two seconds, and then turn on all the power
supply units implemented on the Switch.
(1) If this fault occurs on the BCU, CSU, or MSU, replace
the applicable BCU, CSU, or MSU.
No. Point to be checked Action
1 The power button of the power supply unit is
off.
Turn the power switch on.
2 • The power cable is disconnected.
• The power cable is not firmly connected.
• The power cable is not fixed with a cable
latch.
Perform the following procedure:
1. Turn the power switch off.
2. If you are using a DC power supply unit, turn off the circuit
breaker at the distribution board.
3. Connect the power cable correctly.
4. When possible, use a cable latch to fix the power cable in
position.
5. If you are using a DC power supply unit, turn on the circuit
breaker at the distribution board.
6. Turn the power switch on.
No. Problem Action