Before Cleaning
All connectors on the circuit board including jumper plug, card board, battery and IC must be carefully pulled out before cleaning. Potentiometer, transformer and solenoid coil (inductive coil) must also be removed from the circuit board.
Note: non electronic professional do not do this operation, because if there is no electronic professional technology, It is easy to damage parts and circuit boards during disassembly. Fortunately, there are basically no such components on the circuit board related to the computer] so once the components are in water, the water drops between the gaps or turns are difficult to be swept out by compressed gas and the moisture is difficult to be dried. During disassembly, records must be made one by one to ensure that no errors will be made when the components are recovered after cleaning. Meanwhile, check whether the electrolytic capacitance on the circuit board has leakage or the top bulge. If so, it should be removed and recorded so as to replace the new products with the same value after the circuit board is cleaned. For the circuit board of computer power supply, it is also necessary to check whether there is crack and live welding between the pad of printed circuit and the component foot. Especially, check the high-power component. If there is any crack and live welding, repair welding shall be conducted immediately, and one repair welding is found, otherwise it is easy to be omitted.
Cleaning
- Before cleaning, clean soft paint brush (1 inch wide brush is better) and compressed air with pressure of about 0.1mpa[i.e. 1kg/ cm2] shall be used to remove dust on the PCB board.
- Cleaning can be used to wash circuit board special cleaning fluid (commonly known as washing water), this liquid can be bought in a special shop. If there is no washing water, it can be operated as follows: (now we generally do not need to wash the board water). Wash with tap water first, pay attention to the soft water flow, and do not be too strong. Brush carefully while flushing, and both sides of the circuit board are as follows.
- Use soft brush to dip neutral soap to clean every place of the circuit board carefully and gently, especially the jumper plug, the inside and bottom of the slot (CPU slot, AGP slot, PCI slot, memory slot), the bottom of IC socket, the north south bridge chip, BIOS chip and other IC chips, and the bottom of the large capacitance, etc, During operation, attention shall be paid to avoid the small capacitance and other components installed vertically from the side of the line; If it is found that the soap foam is dirty, it must be washed with clean water and then washed with soap again until the soap is white.
- Then rinse the circuit board thoroughly with clean water. Note: soap water must be thoroughly washed out.
- After the water washing, blow the water drop with dry compressed air with pressure of about 0.1mpa[i.e. 1kg/ cm2], especially the jumper plug, the inside and bottom of the slot (CPU slot, AGP slot, PCI slot, memory slot), the bottom of IC socket, the north south bridge chip, BIOS chip and each other IC chip, the bottom of the large capacitance, etc., and should be purged from different directions, Try to blow all the water drops out of the gap. If there is no compressed air, you can use a rubber hand pump for clock maintenance or camera maintenance, but it can be tiring.
- Wash the circuit board once with secondary distilled water or anhydrous alcohol (let the side with components welded upward, slant the circuit board, and clean the circuit board with clean oil painting pen No. 10-12 to clean it from top to bottom with anhydrous alcohol). Carbon tetrachloride is more effective, but it is toxic and must be careful when using it. Do not use it unless necessary. Carbon tetrachloride is not recommended. So far, cleaning is over, so cleaning, not only clean and thorough, saving money, environmental protection and health; Because the washing water is harmful to the body, it will not be good to pour the waste liquid into the sewer after washing.
Blow water drops with compressed air with a pressure of about 0.1mpa[i.e. 1kg/ cm2]
Especially jumper plug, the inside and bottom of the slot (CPU slot, AGP slot, PCI slot, memory slot), the bottom of IC socket, the north south bridge chip, BIOS chip and other IC chips, and the bottom of large capacitance, etc., and should be purged from different directions, Try to blow all the water drops out of the gap.
The PCB board after cleaning and treatment must be thoroughly dried before it can be put into use. There are many methods. Please refer to the following methods:
- Dry in an oven, and the oven temperature is adjusted to about 80 degrees Celsius for about 24 hours.
- Blow dry with electric hair dryer (industrial or household), this method needs to hold the hair dryer and swing constantly, very annoying! And if the technique is not at that time, it may be dry uneven, especially in those places where the cracks are.
- Put it in the air conditioning room, and let it dry naturally, lasting for more than 36 hours.
- According to the records made during the disassembly of components as the guide, the original parts used for disassembly shall be restored one by one.
- Check whether the installation is qualified.
The circuit board of other equipment can also be cleaned and maintained as above.
