Summary: As we all know, in winter and summer, air conditioners generally need heating and cooling almost every day, so long-term use will inevitably cause some minor problems. Many failures are caused by damaged air conditioner PCBs. So, what are the maintenance methods for common faults of air conditioner PCB? What are the precautions for air conditioning circuit board maintenance?

1. Circuit: (1) If there is a problem with the power supply circuit of the air conditioner PCB, it will be displayed in the form of a blown fuse, which directly indicates that the circuit is short-circuited. (2) The resistance value can be detected with the ohm plug of the multimeter to judge the short circuit part of the FS technology. After finding the short-circuit part, please replace and repair it in time.

2. FS Technology uses temperature detection circuit: (1) When the temperature of the thermistor is low, the resistance value is large; on the contrary, the higher the temperature, the smaller the resistance; the resistance value of 25 degrees is about 5-20.

Air Conditioning PCB Repair-fs Technology (2) It can be measured with the ohm plug of the multimeter. If the measured resistance value is small or infinite, it proves that the thermistor is damaged and must be replaced immediately.

1. Receiver circuit: (1) Use the DC acceleration of the multimeter to directly measure the ground voltage of the power supply terminal and the signal terminal of the receiving terminal. The normal electrode value is +5 volts and the signal electrode voltage is +2.5 volts. (2) If the value is wrong, it should be that the receiving head is damaged or the capacitor is defective. Remove them one by one and find out how to maintain them.

2. The crystal oscillator circuit of FS Technology: (1) After the air conditioner is turned on, use a multimeter to measure the voltage of the two pins of the quartz crystal oscillator, the value is about +2.2 volts; if it is lower than 1.5 volts, the circuit has a problem of stopping vibration. (2) The quartz crystal tube can be removed and judged by the ohm plug of the multimeter. If it shows an open circuit, it means that the quartz crystal tube is good; if it is a short circuit, the crystal is damaged. CPU error.

Multilayer circuit board repair-fs technology

The three conditions of power supply voltage +5V, reset voltage and clock pulse signal are necessary conditions for the normal operation of the CPU of the circuit board, otherwise the CPU will not work normally. Therefore, a multimeter can be used to detect the voltage of its working state. If the voltage value is normal and the whole machine does not work, it can be judged that the CPU chip is damaged. If the CPU fails, just replace the CPU.

Abstract: PCB manufacturing, printed circuit board assembly, PCB soldering technology. In principle, conventional inserts can also be reflowed, often referred to as through-hole reflow. What is the principle of PCB soldering technology? Next, follow FS Technology to learn all about this knowledge.

pcb for keyboard

The principle of circuit board soldering technology 1. Warm up Solvents that increase the viscosity and screen printing properties required for pcbs are required. When starting to evaporate, be sure to control the temperature so that the temperature rise must be slow (about 5°C per second) to limit boiling and splashing and prevent the formation of small tin beads. Additionally, some components are sensitive to internal stress. FS Tech believes that the external temperature of the module rises too fast, which will lead to cracking. This is the experience of FS PCB in the past, and beginners must keep in mind.

The chemical cleaning operation begins. Water-soluble flux (paste) and non-cleaning flux (paste) have the same cleaning action, but the temperature of the two is slightly different. Removes metal oxides and some contaminants from the metal and solder particles to be bonded. A good metallurgical solder joint requires a "clean" surface.

As the temperature continues to rise, the solder particles first melt individually and begin a "rapid" process of liquefaction and surface tin extraction. This covers all possible surfaces and begins to form solder joints.

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1. Reflow FS PCBA believes that this is the most important stage. When all the individual solder particles melt, they combine to form liquid tin. At this point, surface tension begins to build up on the surface of the pin. If the gap between component pins and PCB pads exceeds 4mil (1mil = one thousandth of an inch), the pins and pads are likely to separate due to surface tension, which will result in solder joints.

2. Cool down In the cooling stage, if the cooling speed is fast, the strength of the tin point will be slightly larger, but not too fast, otherwise it will cause temperature stress inside the component.

The above is FS Tech's insights on pcb welding technology. We will publish an article on testing pcb welding quality later, so stay tuned!