PO Error on Landice L-Series Treadmills

Probable Cause

A PO or Pot Out error on the Landice L-Series treadmills such as the L7, L8 and L9, indicates the elevation system is not functioning or the elevation potentiometer is out of range. Causes for a PO or Pot Out error are:

A) Elevation potentiometer is out of calibration
B) Faulty upper display board
C) Faulty pwm/relay board
D) Faulty elevation motor

Corrective Action

A) Confirm elevation system works properly in diagnostics mode.  If so, calibrate the elevation potentiometer.

B) If elevation system does not work properly in diagnostics mode, determine which button or direction has the problem.  Do this by disconnecting the elevation motor from the relay board.  Hold the UP button on display and verify if the UPSW light on the relay board is lit.  Hold the DOWN button on the display and verify if the DNSW light on the relay board is lit. 
  1. If neither lights were lit when corresponding button was held, then inspect the orange (UP) wire and the purple (DOWN) wire on both the wire connector on the relay board and the wire connector on the uppder display board for loose connections or pushed pins.  If all harness connections are intact, then replaace the upper display board.
C) If elevation system does not work properly in diagnostics mode, determine which button or direction has the problem.  Do this by disconnecting the elevation motor from the relay board.  Hold the UP button on display and verify if the UPSW light on the relay board is lit.  Hold the DOWN button on the display and verify if the DNSW light on the relay board is lit. 
  1. If both lights were lit when corresponding button was held, then again hold the UP button on the display and verify if the yellow UP light on the relay board is lit and then hold the DOWN button on the display and verify if the yellow DN light on the relay board is lit.  If neither the yellow UP or the yellow DN lights on the relay board are lit when corresponding button is pressed on display, then replace the pwm/relay board combo.
  2. If both the UP and DN lights on the relay board light up simultaneously when either button is pressed on the display board then replace the pwm/relay board combo.
D) If the UPSW light on the relay board and the DNSW light on the relay board both lit when their corresponding UP or DOWN buttons were pressed on the display and both the yellow UP light on the relay board and the DN light on the relay board both lit as their corresponding UP or DOWN buttons were pressed on the display but the elevation system still is not functioning, inspect the black (UP) wire and the red (DOWN) wire on the 6 pin elevation motor connector to the relay board.  If connections are intact, replace the elevation motor.