The supermarket anti - theft device does not ring or sound an alarm. There may be the following multiple reasons:

1. Power supply problem

* Power indicator light does not come on: Check whether the power indicator light on the device is on. If it is not on, it may be that the power supply is not connected or the fuse is damaged. Check whether the power plug is properly inserted, whether the power socket is firmly connected, and whether the fuse is intact.

* Incorrect input voltage: Check whether the input power supply voltage meets the requirements. The input voltage of Lifangmei supermarket anti-theft alarm should be AC - 24V/AC - 12V*2. If the voltage is too high or too low, it will affect the normal operation of the anti-theft alarm.

* Power supply wiring issues: Check whether there are open circuits or short circuits in the power supply wiring, and whether the external power adapter is working properly. If the adapter is damaged or the wiring is poor, the supermarket anti-theft device will be unable to be powered normally and thus unable to sound an alarm.

2. Equipment Connection Issues

* Poor wiring of alarm lights and buzzers: When the supermarket anti-theft device has a sensing but no sound, check whether the wiring of the alarm lights and buzzers is good, and whether there are loose, fallen off or damaged conditions. The plug of the buzzer can be pulled out and then plugged back in. If it still doesn't work, the buzzer may be damaged and needs to be replaced.

* Antenna connection port is loose or detached: Check whether the antenna connection port is loose or detached. If the antenna is not firmly connected to the motherboard, it will lead to poor signal transmission and prevent the anti-theft device from sounding alarms normally.

3. Environmental Interference Issues

* Interference from surrounding metal objects: If there are large-volume metal objects close to the supermarket anti-theft detector, such as lockers, freezers, and iron cabinets, interference will be generated to it, resulting in reduced detection sensitivity or even failure to detect the anti-theft tag and thus being unable to give an alarm. These metal objects need to be moved away.

* Interference from electrical equipment: If there are other high-power electrical devices within 2 meters, such as cash counters, card punches, computers, cash registers, rice cookers, etc., especially when these devices form a circular coil, they will interfere with the anti-theft device. In addition, within a 10-meter range around the supermarket anti-theft device, there should not be any coiled wires. For example, the network cable of the POS machine should not form a loop; otherwise, it will affect the normal operation of the supermarket anti-theft device.

* Signal Interference: External radio frequency signals can also interfere with supermarket anti-theft devices, causing them to malfunction. If the environmental interference is very severe and all signal indicator lights are on, the system will not be able to work properly.

4. Equipment-related problems

* Master board failure: If the supermarket anti-theft device still doesn't ring after excluding the above problems, it may be that the master board has a fault. For example, some components on certain circuits fail or are damaged, which makes it unable to send out the alarm signal normally. Contact a professional for testing and repair.

* Improper sensitivity setting: If the sensitivity of the supermarket anti-theft device is set too low, it may fail to effectively detect the anti-theft tag and thus cannot give an alarm. The sensitivity can be adjusted appropriately according to the on-site environment. If you are using Lifangmei supermarket anti-theft device, you can consult technicians for specific adjustment.

* Tag Issues: The anti-theft tags used may have problems. For example, the tags may be damaged or decoded, or soft tags are attached to products with metal packaging. In these cases, the supermarket anti-theft detectors will not sound an alarm. It is necessary to check whether the tags are intact and whether they are used correctly.

The above are some reasons why the supermarket anti - theft devices do not ring or give an alarm. If you encounter any problems with Lifangmei supermarket anti-theft device you purchased, you can contact our after-sales service for assistance at any time.