Hardware Troubleshooting 5-7
Troubleshooting the Power Subsystems
—Dial shelf controller card—Powers ON first, followed by remaining logic cards. The PWR
and MBus LEDs should light. The remaining four ala rm LEDs should all brie fly flas h on and
then turn off.
If the MBus LED remains off but the power LED is on, there might be a problem with the
MBus power supply on the card. Replace the card.
—Trunk card—At initial power ON, all LEDs light while the system runs a series of
diagnostics. After the system passes initial diagnostic s, all LEDs go off. The power, host
CPU, and framer CPU LEDs then light to indicate that the trunk ca rd is operating properly.
—Modem card—During normal operation, all five LEDs light at system power up. When the
modem card CPU software image starts running, it shuts off the modem LED. The power,
host CPU, and modem LEDs then light to indicate that the modem card has passed
diagnostics and is operating properly.
If the dial shelf processor component LEDs do not light as described, proceed to the section
“Troubleshooting the Processor Subsystems.”
Troubleshooting the Power Subsystems
The Cisco AS5800 is designed to minimize problems in the power subsystem. T he power subs ystem
includes the router shelf power supplies, the dial shelf PEMs and filter module, and the AC-input
power shelf (if used).
The access server comes with two DC power supplies in both the router shelf and the dial shelf,
which allow you to replace power supplies while the system is operati ng. Ho we ver, if you are using
an AC-configured system and you discover a faulty PEM, you must po wer off the system before
performing a replacement.
Caution If your system requires the AC-input power shelf for AC-to-DC conversion, you should
schedule a time for system maintenance and replace the PEM at that time. Refer to the document
AC-Input Power Shelf and P ower Supply Installation and Replacement (Part Number 78-4659-xx)
for installation and replacement instructions.
The failure of a single power supply in the router shelf, the dial shelf, or the AC-input power shelf,
if used, will not stop the access server from operating; however , to main tain power redundancy, both
power supplies in each unit must be receiving power.