The problem of false alarms usually comes with apex locator on the conditions as below:

Short Circuit
It displays exceeding before the measuring tips reach the right position.
1. The file tip touches the metal crown during operation. Just keep them separate or no touching!
2. There is some liquid like live pulp between the pulp cavity and the adjacent tooth, which forms a circuit loop. Thus don’t forget to make the root canal blotted dry by cotton before apex measuring.
3. There will form a short circuit when a side branch occurs in the root canal. When the file tip reaches the orifice of side branch, the locator alarms a tip exceeding. A It is supposed to take a dental x-ray to confirm whether a side branch in the root canal.

Open Circuit
There is never a signal tells whether you have reached root tip.
1. There may be a loose or broken connection between the line and main unit interface, the file clip, etc. Just check them!
2. The root apex tip is completely calcified or filled with deposits that causes no circuit loop between the file and the oral mucosa. The current loop will occur between the pulp cavity and the adjacent root canal. Thus any obstructions should be removed before measuring.

Machine Failure
If the apex locator fails to work, please contact the manufacturer or dealer in time for a professional repair.