- Whether the customer has moved the parameters.
- If it is the signal line of the coil (D4 type is not), use a magnet against the base and slide it left and right to get an instantaneous flow.
- Ask the customer if there is a signal that is not present after repeatedly turning the meter head, if so, the signal has fallen out.
- If the main card is stuck, use a screwdriver or other tool to move it. If the rotation is not flexible, the bearings are worn out.
