Minelab F3 Operation Manual page 25

F3 Operations Manual
The F3 will emit a series of four rising tones over 12 seconds
(internal diagnostic checks occurring). At the completion of the
Start-Up Tones listen for the low volume Threshold Tone.
Figure 16: Switch On
If the Threshold Tone is steady continue with STEP 2. If the
Threshold Tone is noisy or uneven when the coil is stationary,
perform a Noise Cancel (Section 4.3.a).
If the Threshold Tone is steady but seems louder than normal
when the coil is away from the ground and metallic targets,
perform an Audio Reset (Section 4.3.b).
23