If the underground metal detector is not working properly, sound can't be decreased after increasing, maybe the battery power not enough, charge the battery.2. Don't press the button on the metal above,
should press button in the absence of metal surface, can't hold he button when detecting in
quy trình.
3. If the instrument can't keep the "Critical sound" indicating the instrument failure, should send to
nhà máy để sửa chữa.
