The main fire engine shows "circuit failure", how to deal with it?

1. First, record the total number of fault points. Generally, the types of equipment for fault inspection are divided into two categories: bus equipment and control equipment. If the fault type is a full loop device, we can identify it as a bus fault. If the fault type is control equipment, it is necessary to detect the control power supply, which is generally 24V DC power supply. First of all, let's introduce the fault detection and maintenance of bus equipment.

2. Open the back panel of the host and find the corresponding signal line loop number. And use a multimeter to select DC gear to measure the line voltage (the signal line voltage of domestic equipment is generally around 18V, which is not constant). If the voltage is normal, it can generally be judged that the non-loop board is faulty. At this time, remove the signal line of the faulty circuit and measure whether the circuit board voltage is normal. ) After the circuit board fault is basically eliminated, remove the signal line bus of the faulty circuit and measure its voltage with a multimeter. This method can detect whether it is connected in series with other circuits or interfered by other power signals. If the test result is that there is voltage, the type of equipment in which the signal lines are connected in series is judged according to the voltage level. If the voltage measured after disassembly is zero, the resistance between lines should be detected. If the resistance between lines is too small, it can be judged that there is a short circuit between lines, and the resistance between lines is generally greater than1000 k. If the resistance between lines is normal, the resistance between positive and negative power sources and ground should be measured. Be careful not to use a shaking table to prevent overvoltage from damaging the equipment. Through a series of tests, the cause of the failure was determined.

3, find out the cause of the fault, should find the corresponding circuit junction box, generally in the weak current shaft. Find the signal line branch in the junction box. Take them all off and measure the resistance between the wire and the ground one by one. Find out the fault line in detail, and then reconnect the normal signal line to the main line section. Find out the fault range through the Chinese character definition of the host.

4. Go to the fault site through the Chinese character definition of the host. First, according to the failure time of the main engine, ask the field personnel whether there are any related discoveries and construction operations during this time period, and generally find the failure site quickly. If you can't understand the relevant situation, you can take the method of subsection and branch according to CRT drawings, that is, according to the field situation, remove the terminal board from the fault area and push out the fault branches one by one. Finally, the corresponding fault point can be found.