||The IEC power receptacle and power switch do not appear to contain a line filter.
The manufacturer placed separate toroids on the treadmill belt DC motor power and ground conductors.
I measured the size of each toroid as 31 mm OD, 18.3 mm ID, and 15.5 mm H
(similar to the dimensions of an FT-114-A toroid.)
The two DC motor power conductors (red and black) each make 4 turns through one of the toroids.
The single DC motor ground conductor (green/yellow) makes 4 turns through a separate toroid.
I do not know what toroid material was used, and I did not measure its permeability.
I also did not measure the drive waveform with an oscilloscope.