Final answer:
The fuzz burn off feature of the main XMSN is disabled when it is not necessary to remove noise from the digital signal.
Step-by-step explanation:
The fuzz burn off feature of the main XMSN is disabled when it is not necessary to remove noise from the digital signal. This feature is typically used to filter out unwanted noise or interference during signal transmission. For example, in a wireless communication system, the fuzz burn off feature may be disabled when the signal strength is strong and the noise level is low, as the noise does not significantly affect the signal quality.