Motor Controller Comm Bad Error on LifeFitness 9700HR, 9100 and 9500 Next Gen Treadmills

Probable Cause

  1. Loose wire harness.

Corrective Action

  1. Check Harness Between Lift and Controller -P9/P3.
    1. Reset connections at wax/lift PCB connector P9 and motor controller PCB connector P3. 

Functional Description

The wax/lift/power supply board acts as a junction board that interfaces with the:

  • Display Console
  • Frame Tag
  • Home Switch
  • Lift Motor
  • Wax Motor
  • Power Supply


Wax/Lift Power Control Board (PCB)

Functional Description

The Motor Controller PCB is a single-phase AC input PWM variable frequency three(3) phase AC output motor controller. Specifically, the controller input is configured as a full-wave bridge for 230 volt AC input, and as a voltage doubler for 120 volt AC input. The resultant DC bus voltage is processed through a microprocessor-controlled six switch DC to AC inverter. The output is three-phase power with pulse width modulation of both voltage and frequency.

NOTE: The motor controller design utilizes a 'hot' supply. This means the entire board will be at elevated potentials relative to earth ground any time the circuit is active. All measurements should be conducted with isolated equipment. Additionally, there is considerable energy stored within the circuitry for up to 90 seconds after power is removed from the circuit. Personnel working with this equipment should be trained and adequate precautions should be used whenever working with this equipment.


Motor Controller PCB



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