Introduce common faults and maintenance methods of lithium-ion battery chargers

1. The fuse tube is blown: carefully check the various components on the circuit board to see if the appearance of these components is burnt or there is electrolyte overflow, smell-smell whether there is any peculiar smell; then measure the resistance value of the power input terminal to see the local short circuit phenomenon; then Then measure whether the power filter capacitor can be charged and discharged normally, whether the switching power tube is broken down, whether the UC3842 and surrounding components are broken down, burned out, etc., if the components are damaged, replace them. 2. No DC voltage output or unstable voltage output: First, use a multimeter to measure whether each component of the high-frequency pulse transformer is damaged, and eliminate the breakdown of the high-frequency rectifier diode and load short-circuit; then measure the DC voltage of each output terminal to see Whether the control circuit of the power supply is faulty; then use a multimeter to statically measure whether the rectifier diode and the low-voltage filter capacitor in the high-frequency filter circuit are damaged. If the above-mentioned components are damaged, replace them with new ones. 3. There is no DC voltage output, but the fuse wire is intact: first judge whether the charger's variable control chip UC3842 is in the state of being in the state or has been damaged. If these pins are not broken down, but the charger still cannot start normally, it also shows that the UC3842 is damaged and should be replaced directly. 4. The cooling fan does not rotate: first use a multimeter to measure-whether the transistor controlling the fan is damaged. If the tube is not damaged, it may be that the fan itself is damaged. You can unplug the fan from the circuit board and connect it in addition A 12V direct current (note the positive and negative), see if it is rotating, and also see if there is any foreign matter stuck; if you swing the fan's wire, the fan will rotate, it means that there is a broken wire inside the wire or the connector is in poor contact. Replace the components according to the above situation. 5. The power supply does not start: plug in the power supply, the large capacitor has a voltage of 300V, unplug the power supply, and measure the voltage at the end of the large capacitor 2 or 300V does not drop. After discharging the capacitor, replace the starting resistor. The starting resistance is in the power input part, the resistance is 150K and the power is 2W. 6. The power supply does not start: plug in, the large capacitor has a voltage of 300V at 2 terminals, unplug the power supply, the large capacitor voltage slowly drops, check all the circuit boards for de-soldering phenomenon, after the repair soldering is completed, replace the 3842 with a new one Yes, just power on and test the machine. 7. Flashing light: first repair the circuit board and test the machine again. If it still flashes, please check the output terminal sampling resistance. 0.1 Euro. 3W power. Connect it to the negative end of the output line and replace this resistor with a new one. 8. The output voltage is high, power on, the voltage is higher than 70V, charging does not turn the light, first repair the circuit board, and try the machine again, if the voltage is still high, please replace the photocoupler, try the machine again, or the output is high , Replace the 431 reference regulator, and test the machine again. 9. The output voltage is unstable: first repair the circuit board, then test the machine, and then replace the output capacitor 63V470UF with a new test machine. 10. Charging does not turn the lights: use the tester to test the data, and then replace the 358 or 324 with a new test machine. 11. The charging is unstable, sometimes it can be charged, sometimes it can't be charged. Use the tester to check the data, then replace all the input and output power cords with new ones, repair the circuit board and test the machine. 12. Power on and burn insurance: first check whether the power tube is broken down, if not, replace all 4 rectifier diodes with new ones, and test the machine. 13. No output when power on: power on and test the machine, the large capacitor 2 has a 300V voltage, and it slowly drops. First, check whether the large diode at the output end has broken down, repair the welding, and try the machine again. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: How to detect the loss of 18650 lithium battery pack?