(1) UV fluorescent tube is not bright
There are usually two situations when the ultraviolet fluorescent tube does not light up: First, the 220V city power does not enter the mosquito killer circuit, and there is no voltage on the high-voltage power grid at this time. In this regard, you can first check whether the 220V mains power is normal, and if it is normal, check whether the power plug and socket are disconnected or have poor contact. If there is still no problem, you need to disassemble the mosquito killer and check it. Usually, it is caused by the loose solder joints of the power cord. The fault can be eliminated after re-soldering. A few may also be caused by an internal open circuit of the power cord, which can be reconnected or replaced with a new one. Second, the 220V city power has entered the mosquito killer circuit, and the voltage of the high-voltage power grid is normal, which indicates that the fault is only in the UV fluorescent tube circuit. The shell of the mosquito killer can be detached. First, check whether the lead between the lamp tube and the printed circuit board is disconnected or disconnected. If so, reconnect it; if not, check whether the lamp tube and the lamp holder are in good contact. If the contact is not good, you can re-tighten the lamp. If there is no problem with the contact, then the lamp is broken. It is common that the lamp is naturally aging and the lamp leaks after the long-term use. Generally, you have to replace the new lamp with the same specification.
It is worth pointing out that the service life of the lamp is not only related to its own quality, but also has a lot to do with the method of use and the fluctuation of the mains voltage. Therefore, the use of mosquito killers should minimize the switching power supply, preferably only once a day, and it is best not to use them indoors where the mains voltage is too high or too low, so as to avoid premature aging of the lamp and prolong its service life. .
(2) The ultraviolet fluorescent tube is bright, but the high-voltage power grid has no voltage
The method of judging whether there is voltage on the high-voltage power grid has been mentioned before. There are two main reasons for this failure: one is that the lead of the voltage doubler rectifier circuit or the conductor of the printed circuit board is open, usually by visual inspection or multimeter measurement, the fault point can be found quickly, and it can be carefully re-soldered. Solve the problem. The second is that the diodes, resistors or capacitors in the voltage doubler rectifier circuit are damaged. On-road inspections can be carried out one by one during maintenance. Since there are not many components, the fault can usually be found quickly. If the diode is damaged, it can be replaced with 1N4007 or 1N4006; if the capacitor is damaged, it is recommended to replace it with a non-polar capacitor with the same capacity and withstand voltage greater than or equal to 400V. In order to reduce costs, some manufacturers of mosquito killer lamps use capacitors with lower withstand voltage specifications, so that the failure rate is higher, and replacement of high-quality capacitors during maintenance can avoid or reduce the occurrence of such failures. In addition, the high voltage will disappear when there is a short-circuit fault in the high-voltage power grid. Therefore, check whether the high-voltage power grid has a short-circuit fault during maintenance. If there is, it should be eliminated.
(3) UV fluorescent tubes often flicker (flicker)
This kind of failure is usually caused by low mains voltage, and some are caused by lamp aging. If the measured mains voltage is normal, the lamp can be replaced. You can also try to increase the capacity of C1 to 0.2~0.47μF, but this is only a stopgap measure, and the original capacity should be replaced when replacing the new lamp.
(4) The low voltage of the high-voltage power grid and the poor effect of killing mosquitoes are generally caused by the obvious reduction of the capacitor capacity in the voltage doubler rectifier circuit. You can check one by one and replace the bad capacitors. In addition, it should be noted that the effectiveness of the mosquito-killing lamp is closely related to the correctness of the method of use, so be sure to pay attention to the method of use.