Stanley Fatmax Stud Finder 400 Manual Verified -

Diagnosis: The unit is saturated with interference. Verified Fix:

Finding the edge:

The display will flash “STUD” and show a center line when directly over the center.

Diagnosis: You have shifted your grip, lifting the back edge off the wall. Verified Fix: Use the "Pinky Drag" technique. Keep your pinky finger touching the wall behind the device to act as a pivot, ensuring the back remains flush throughout the scan. stanley fatmax stud finder 400 manual verified

The 400 cannot distinguish live wires from studs. If you get a beep in a location where no stud should logically be (e.g., 12 inches from a known stud), it might be a wire. Turn off the room’s power and use a non-contact voltage tester to verify. Diagnosis: The unit is saturated with interference