Troubleshooting is done on a faulty LS-671/VRC. The steps to determine if a LS-671/VRC is faulty and how to
troubleshoot it are as follows:
When an LS-671/VRC is received from unit maintenance, inspect it for damage. Repair any damage
before proceeding with testing. See section IV if repairs are necessary.
Verify the symptom. Perform the operational check found in paragraph 17-9. This will direct you to the
correct troubleshooting flowchart or identify the fault.
Troubleshoot the LS-671/VRC using the flowchart. It will identify the defective module or component.
Replace the defective module or component. Follow the procedures in section IV.
Verify the repair.
Repeat the operational check in paragraph 17-9 that failed. If it passes, then
continue with the rest of the operational check. When the operational check is passed, the LS-671/VRC
can be returned for use.
The flowcharts provide views of speaker CCA test points. These test points are used to fault isolate to a defective
component. See figure 16-3 for the overall layout of the speaker CCA and test points.
17-11. TEST PRECAUTIONS AND NOTES.
Set the test power supply to OFF before connecting or disconnecting a test setup. Current
capacities are large enough to cause personal injury. Equipment can also be damaged if care is
The Principles of Operation section, functional block diagrams, and schematic diagram figure
FO-30 can be used to help fault isolate any unusual problems that might not be covered in the