Specifications

Chapter 4 - Troubleshooting and Diagnostics FLM-1 Installation & Operation Manual
4-2 Fault Isolation and Troubleshooting 09/01/01 4:29 PM
Local Loopback
When FLM-1 performs a local loopback, the data from the local transmitter
is looped back to the local receiver at the digital level, thus checking all
local digital circuitry for proper operation.
To activate the test, press the LLB push button located on the front panel. If
the local unit is operating properly, the yellow TEST indicator should light
up and all other indicators should be OFF.
If the local and remote units are properly connected via the main channel,
this test also checks the following:
• Local transmitter analog interface
• Remote analog section
• Digital receiver section.
In this case the yellow TEST indicator on the remote unit should also be lit
up.
Remote
Loopback
The remote loopback loops back data from the remote receiver to the
remote transmitter, thus checking:
• All local digital circuitry
• Both local and remote analog interfaces
• Main channel link
• Remote digital receiver section.
To activate the test, press the RLB push button on the front panel. If both
local and remote units operate properly, the yellow TEST indicators should
be lit at both units and all other indicators should be OFF.
4.3 Fault Isolation and Troubleshooting
The symptoms and corresponding procedures listed in Table 4-1 will help
you identify, isolate, and correct faults in accordance with the tools
available.
Warning
These service instructions are for use by qualified personnel only. To
avoid electric shock, do not perform any servicing other than that
contained in the operating instructions unless you are qualified to do so.