1. The ultraviolet fluorescent lamp is bright, the powe […]
1. The ultraviolet fluorescent lamp is bright, the power grid has no high voltage, and the mosquito is not extinguished.
Analysis and overhaul: According to the analysis of the fault phenomenon, the ultraviolet fluorescent lamp is bright, indicating that the 220V mains enters the mosquito killing lamp circuit, and the high voltage of the power grid is mostly caused by the damage of the relevant components of the double voltage rectifier circuit. During maintenance, first check the printed circuit board (see Figure 3) for signs of damage such as scorch, cracking, and shell bulging. Then use a multimeter to measure T2, R1, R2, VD1, VD2, C1, C2. Damage, at the same time need to check whether the V+, V- high voltage power supply leads are off. The two-voltage rectifier circuit has a simple structure and few components, and the fault is usually found very quickly. According to experience, VD1, VD2, C1, C2 are mostly damaged. According to Figure 2, after the component electrical parameters are replaced, the V+ and V- high voltages of the VE are measured and normal, and they can be put into normal use.
2. The anti-mosquito effect is not ideal.
Analysis and maintenance: The anti-mosquito effect is not ideal, usually caused by two reasons:
1. The capacity of the capacitor Cl or C2 is significantly reduced, resulting in a low voltage. C2 is a 0.2uF/2000V non-polar capacitor, which can be replaced by a non-polar capacitor of the same specification. The required withstand voltage should be sufficient.
2. There are many pairs or partial electrodes of the grid vE that are in poor contact with the electrode connection line, and most of them are caused by oxidation or excessive accumulation of electrodes with a long period of use. Refer to the disassembly and assembly method to remove the electrode at the 6th point, polish the oxide, clean the dirt and reset the electrodes. Use the crochet hook to hook the electrode connecting wires one by one to the root of the electrode, then use a multimeter to touch the high-voltage power lead connecting point, and the other pen to touch each electrode one by one. The measurement indications are turned on normally, as shown in Figure 4. If there is any problem, adjust the tension of the electrode cable to make it in good contact with the electrode.
After the above-mentioned overhaul, the power is turned on, and the DC high voltage of the high-voltage power grid V+ and V- is measured by a multimeter to be about 1250V. If the multimeter does not have a DC high voltage block, turn off the power supply and touch the adjacent two electrodes with a screwdriver. The spark is bright and the discharge sound is loud, indicating that the DC high voltage is almost normal.
3, high-voltage power grid fire, accompanied by "squeaky" sound.
Analysis and overhaul: The fault phenomenon indicates that there is a short circuit fault in the power grid. The main reason is that mosquitoes with large bodies such as moths or dirt stick to the two electrodes and cause discharge when exposed to humid air. Unplug the power plug and short-circuit the electrode to completely remove foreign matter. The fault is eliminated.