With the rapid progress of technology, the use of PCB boards is becoming more and more widespread, and more and more customers of the line will have such problems:
How should the PCB circuit board be maintained? How can I make the life of the circuit board longer?
Now share some knowledge of PCB circuit board maintenance by Pineapple Manufacturing Platform.
PCB circuit board uses printed etching resist method to make circuit lines and graphics. Circuit board manufacturers can be divided into single-sided pcb boards, double-sided circuit boards and multilayer circuit boards according to the number of circuit layers. Common multi-layer boards are generally 4-layer boards or 6-layer boards, and complex multi-layer boards can reach more than ten layers.
There are both high-speed logic circuits and linear circuits on the circuit board. They should be separated as much as possible, and the ground wires of the two should not be mixed and connected to the power-side ground wire respectively. Try to increase the ground area of the linear circuit as much as possible.
So how should the PCB circuit board be maintained?
I. Half-year maintenance:
Observe whether the electronic components in the circuit produced by the circuit board factory have passed the trace of high temperature, and the electrolytic capacitor has not swelled up. If necessary, replace it.
The PCB circuit board is cleaned of dust every quarter. It can be cleaned with a special cleaning solution for PCB circuit board. After the PCB circuit board is cleaned of dust, the PCB circuit board can be dried with a hairdryer.
1. Clean up the dust on the PCB circuit board.
2. Sampling the electrolytic capacitor capacity in the PCB circuit board. If it is found that the electrolytic capacitor’s capacity is less than 20% of the nominal capacity, it should be replaced. Generally, the electrolytic capacitor’s life should be replaced in about ten years to ensure PCB circuit The performance of the board.
3. For high-power devices coated with thermal grease, check whether the thermal grease is dry. For dry solids, remove the dry thermal grease and apply new thermal grease to prevent PCB circuits. The high-power devices in the board burned out due to poor heat dissipation.
Third, cleaning and maintenance
1. Preparation before cleaning Carefully pull out all connectors on the circuit board, including jumper plugs, card boards, batteries, and ICs. Potentiometers, transformers, and solenoid coils (inductance coils) must also be removed Remove from the circuit board. [Caution: Non-electronic professionals are not allowed to do this operation, because if you do n’t have the electronic professional technology, it is easy to damage the parts and circuit board during disassembly. Fortunately, computer-related circuit boards are basically Without these components] Therefore, once the components enter the water, the water droplets in the gaps or turns are difficult to be blown out by compressed air and the water is difficult to be dried. Records must be made one by one when disassembling to ensure recovery after cleaning. No mistakes. At the same time, check the electrolytic capacitor on the circuit board for leaks or bulging on the top. If so, remove it and make a record so that it can be replaced with a new equivalent product after the circuit board is cleaned. For the circuit board of the computer power supply, you should also check whether there is crack live desoldering between the pads of the printed circuit and the component pins. Special attention should be paid to inspecting high-power components. One repair welding one, otherwise it is easy to miss.
1) Before cleaning, use a clean soft paint brush (1 inch wide brush is better) and dry compressed air with a pressure of about 0.1Mpa [ie 1kg / cm2] to remove dust on the circuit board.
2) A special cleaning solution (commonly known as plate washer water) for cleaning circuit boards can be used for cleaning. This solution can be bought at specialized stores. If there is no washing water, you can do the following: (Now we generally do not use washing water) Rinse with tap water first, pay attention to the water flow should be soft, not too strong, brush gently with a soft brush while punching, both sides of the circuit board Both are true.
3) Then use a soft brush with a neutral soap to carefully and gently clean every place on the circuit board, especially the inside and bottom of the jumper plugs, slots (CPU slot, AGP slot, PCI slot, memory slot) The bottom of the IC socket, the north-south bridge chip, the BIOS chip and the bottom of every other IC chip, the bottom of the large capacitor, etc. should be carefully cleaned. During operation, care should be taken not to erode the small capacitors and other components installed vertically. The soapy foam is very dirty. After washing it with water, wash it with soap until the soapy foam is white.
4) Then slowly rinse the circuit board thoroughly with clean water. Note: The soapy water must be thoroughly washed away.
5) After washing with water, blow off the water droplets with dry compressed air at a pressure of about 0.1Mpa [ie 1kg / per square centimeter], especially the jumper, socket (CPU socket, AGP slot, PCI slot, memory slot) The inside and bottom, the bottom of the IC socket, the north-south bridge chip, the BIOS chip and every other IC chip, and the large capacitors should be blown from different directions, and try to blow all the water droplets in the gap. clean. If you do not have compressed air, you can use a rubber hand pump for watch repair or camera repair, but this can be tiring.
6) Wash the circuit board again with slightly distilled water or absolute alcohol. (Let the component with the component side facing up, place the circuit board at an angle, and use a 10-10 clean oil brush to apply absolute alcohol from top to bottom. Down for cleaning). The use of carbon tetrachloride is more effective, but it is toxic and must be used with care. Do not use it unless necessary. Carbon tetrachloride is generally not recommended. At this point, the cleaning is finished. This way of cleaning will not only be clean and thorough, save money, be environmentally friendly and healthy; because the washing water is harmful to the body, let alone the waste liquid after washing is surely not good.
3. Use dry compressed air to blow off water droplets, especially the inside and bottom of the jumper plug, socket (CPU slot, AGP slot, PCI slot, memory slot), the bottom of the IC socket, the North-South bridge chip, the BIOS chip and The bottom of every other IC chip, the bottom of the large capacitor, etc., should be purged from different directions, and strive to blow all the water droplets in the gap clean.
4. The printed circuit board must be thoroughly dried before being put into use after cleaning. There are many methods, please refer to the following methods:
1) Dry in an oven. The oven temperature is adjusted to about 80 degrees Celsius for about 24 hours.
2) Dry with a hair dryer (for industrial or domestic use). This method requires the hand to swing without stopping the hair dryer, and if it is not done properly, it may dry unevenly, especially in the gaps.
3) Place it in an air-conditioned room and allow it to air dry for more than 36 hours.
5. Follow the records made when disassembling the components as a guide to restore the originals used one by one.
6. Check the installation for compliance. The circuit boards of other equipment can also be cleaned and maintained as above.