SAMPLE EQUIPMENT TROUBLESHOOTING PROBLEM

Figure 1-7.—Relay lamp ladder diagram. The relay lamp ladder diagram is a troubleshoot- ences in fire-control equipment, each fire-control sys- ing support document for the signal-flow diagram and tern has its own troubleshooting philosophy. How- the maintenance turn-on procedure. It is also used as ever, they all use the basic troubleshooting documen- the prime troubleshooting document for equipment tation (or a modification or combination of the basic switching problems. documentation) covered in this chapter. The relay lamp ladder diagram traces the energiz- ing path for the relay coil or indicator lamp from a common interface point appearing on both the power- distribution diagram and the ladder diagram. It traces through the equipment, to the respective relay coil or indicator lamp, and to a common return power inter- face. The relay lamp ladder diagram shows cabling, terminal connections, relay contacts, switches, and lamps in the energizing path. SAMPLE EQUIPMENT TROUBLESHOOT- ING PROBLEM.— Because of the inherent differ- This sample problem uses the checkout procedure, and the problem-directory and pyramid-diagram methods of troubleshooting. In these methods, the technician sets up, adjusts, and verifies equipment operation according to a set of steps in the checkout procedures shown in table 1-8. If the function being tested at a particular step fails, the technician refers to that same numbered step in the problem directory to isolate the faulty compo- nent. A sample problem directory is shown in table 1-9. 1-21