Chapter4 Troubleshooting the Installation
Troubleshooting an ACPower Sub system
4-6
CiscoXR 12406 Router Installation Guide
OL-13831-01
Troubleshooting an AC Power Subsystem
ACPEMs provide –48 VDC OUTPUT. The +5VDC OUTPUT from the CSF
powers the MBus module on each card in the system. The MBus module, in turn,
control the DC-DC converters also present on each card in the system. The
DC-DC converter takes –48 VDC from the power supply and converts it into +2.5,
+3.3 and +5 VDC, which is distributed to the card circuitry.
ACPEMs ar e monitored by the MBus module and the RP for over- or
undervoltage and over- or undercurrent conditions.
Begin checking the AC-input power subsystem by first looking at the LEDs on the
AC-input power supplies. Figure 4-1 shows the location of the LEDs on the power
supply.
Figure4-1 AC-Input Power Supply LEDs
1AC-input power supply 4Captive screws on release levers
2Handle 5LEDs
3Power standby switch ––
57916
1
3

2 5

4