C-COR.net FlexNet E7, Руководство по эксплуатации оборудования

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5-2 FlexNet ® 700 Series Line Extender Rev F
5
Quick Forward Outage Check
This check is not a comprehensive test of all amplifier functions. The steps listed here can help you
quickly determine whether or not an amplifier is causing a signal outage to subscribers downstream in
the forward path, especially when no automated status monitoring is used.
➤
To check for signal outage in the forward path
1. Measure the output signal at the Port 3 external testpoint of the suspect line extender using
a signal level meter. Measure an active frequency/channel that has historical (or designed)
values to compare against.
2. If the output signal is at a reasonable level, check devices further down the signal path. If not,
check the input signal level at the Port 1 external testpoint.
3. If the input signal is at a reasonable level, but the output signal is not, use the following
troubleshooting sections in the book to see if this line extender is the source of the outage. If
the input signal is not at a reasonable level, check amplifiers closer to the signal source or
headend.
Reasonable levels are determined by the system design. Your system map and Amplifier Data Sheets
can give you the designed and historical levels. When trying to fix an outage quickly, a much wider
range of values may be accepted than when balancing or sweeping a system. You can usually fix smaller
problems after service is restored.
When you have many amplifiers to check, a good general method for finding the source of an outage
is the 50/50 method. The 50/50 method consists of testing for RF signals and power problems at a
device halfway through the cascade (or problem leg). Keep dividing the problem sections in half until
you isolate the malfunction. You can combine this method with other methods.
An E7 Line Extender that outputs reasonable RF signal levels may not pass power to the next device
(likely due to a blown fuse). The lack of power passing is then caught when the next active device in
the signal path is checked, which leads you back to the faulty amplifier.
Power Troubleshooting
Use the appropriate procedures (based on power supply type) given in Voltage Testing on page 4-2
through 4-4 to troubleshoot the power supply.