1. First simple, then complex. Solve the problems that are easy to solve first, and then solve the problems with greater difficulties. Don't get stuck in a difficult problem at the beginning.
2. First outside, then inside. Firstly, the exposed, easily accessible and easily disassembled parts shall be inspected, and then the parts that are not easy to be touched and disassembled shall be inspected.
3. Ripen first, then raw. The common fault parts of the mixer truck are checked first, which can quickly determine the fault location and save time and effort.
4. First static, then dynamic. Here, "static" refers to the static state without starting, while "dynamic" refers to the working state after starting the engine. Do not start the car blindly. Do necessary safety inspection and electrical performance test (to see if there is leakage, ignition or short circuit), and then start the work to ensure the safety of the car.
5. Power supply before load. Power failure is one of the most common faults, so the power supply should be checked first after the electrical part fails.
6. First general, then special. First check the general fault, then check the special fault.
7. Public use first and then private use. We should first solve the problems of commonality and common problems of all parts, and then solve the problems of individual and special circuits.
8. Section inspection. Section inspection of mixer is to detect and analyze the system suspected to have mixer fault section by section in fault diagnosis until the trouble point of mixer is found.