If an instrument will not take a reading, check the following;
Is it 'locked-up'? That is, can the user press a button and make the display change? If it is locked up, try to Reset the instrument.
If the instrument responds to the buttons, but will not read, check the read actuator.The read actuator is the "knob" or "screw" that sticks out from the top of the shoe and makes contact with the read switch. The actuator is factory adjusted and is held in place with a LocTite glue. When measuring, the switch should make a soft click just as the instrument touches the surface. If the actuator has become loose, and no longer makes contact with the switch, have the customer adjust it and glue it in place.
If all of the above fails, the unit must be returned for service.
