CYBEX LCX 425T - TREADMILL
HOW TO REPLACE MOTOR BRUSHES -
Motor Brushes 110 VAC (Product Numbers SK-18553)
Motor brushes are wear items that will periodically need to
be replaced.
Both drive motor brushes must be replaced as a pair. This
will ensure even commutator contact and brush wear. However, the negative brush
will wear 20% faster than the positive brush. Therefore, always measure the
negative brush length to determine whether you should replace the pair. The
negative brush is located closest to the front of the frame. You should still
check the positive brush for cracks or chips.
It is not necessary to
remove the drive motor in order to reach the motor brushes.
Tools Required
Phillips head screwdriver
Flat head screwdriver
7/16” open-end wrench
1/2” open-end wrench
[Keep wet items away from inside parts of the treadmill.
Electrical shock could occur even if the treadmill is unplugged. A qualified
service technician should perform motor brush removal and replacement.]
Verify the kit
contents shown.
A. Brush Assembly, 110 VDC, Red (1)
B. Brush Assembly, 110 VDC, Black (1)
C. Brush Retainer, Molded (2)
D. Wire tie, 18”, EH-12260 (1)
E. Wire tie, 9”,
EH-00986 (3)
Remove motor cover.
Using a Phillips head screwdriver loosen but do not remove
the two screws securing the left motor cover in place. Loosen the two screws
securing the right motor cover.
Lift the top motor cover up and off of the treadmill.
Elevate the treadmill.
Without standing on the belt, press the Start key and begin
running the treadmill.
Press the up arrow and
elevate the treadmill fully.
Disconnect the power.
While the treadmill is still fully elevated and running
unplug the power cord from the wall outlet.
Access drive motor.
Carefully lift the rear of the treadmill until the top of
the console is resting on the ground. { Drive belt is under tension. Do not
pinch fingers while releasing tension.}
Release drive belt tension by placing the Phillips head
screwdriver into the square hole located in the bottom of the idler pulley
assembly.
While pushing down on the Phillips head screwdriver
carefully slide the drive belt off of the drive motor pulley. Slowly release
tension on the idler pulley assembly. [WARNING: Motor plate is heavy and will
drop down when motor plate bolts are removed.]
Using a 1/2” open-end wrench remove the two motor plate
bolts and washers.
Slowly and carefully lower the drive motor plate.
Disconnect the motor cables.
Locate the red and black drive motor cables exiting the
drive motor and connected to A1 and A2 on the lower control board.
Disconnect the two motor cables from the lower board.
WARNING: Avoid touching lower board components such as resistors and
capacitors.
Cut the wire ties securing the drive motor cables to the
drive motor housing and other cables on the lower control board.
Remove the ferrite from the two motor cables.
Using the 7/16” open end wrench loosen the nut securing the
wire clamp retainer at the end of the motor. Remove drive motor cables from
retainer.
Remove the black brush assembly.
Using a large flat head screwdriver pry out the brush
retainer on the drive motor that secures the black wire. The brush and spring
will pop out.
Examine the brush and commutator.
Inspect the commutator by looking through the top brush
holder into the motor. Slowly spin the motor by turning the flywheel. Look for
noticeable damage and for signs of wear such as arcing, pitting, burning, or
uneven wear. Commutator bars that are ‘dirty penny’ brownish copper are in
great condition. Also, some commutator bars may be pitted or blackened on one
edge. Too many of these indicate a worn commutator, and the motor should be replaced.
The commutator may be cleaned with narrow commutator stone if carbon build-up
is present. Brush dust can be loosened from the motor surfaces where the brush is
placed by lightly filing the surfaces. Dirt and brush dust should be vacuumed
out of the motor.
Inspect the brushes for signs of excessive wear or cracks.
The motor brushes must be replaced if one or both is worn to .375” (9.5 mm) or
less in length, is broken or chipped, has a broken spring, or binds in the
motor.
Replace the black brush assembly.
Slide the new brush into the motor brush holder. If the new
brush does not slide in and out easily, the edges or corners of the brush can
be lightly filed down. If cleaning the motor, and filing the brush doesn’t
allow the brush to slide easily in the brush holder, the motor should be
replaced.
The motor may make a clicking noise as new brushes wear in.
If you reinstall the original brushes it is good to install them facing their
original position. Reversing the orientation of the brush can cause a clicking
noise during operation until the brushes wear in.
Fully compress the spring by pushing as far into the brush
holder as possible.
While compressing the spring, place the new brush retainer
into the motor housing until the brush retainer is fully seated into the motor
housing.
Repeat steps for the
red brush assembly.
Connect the drive motor cables.
Place the new drive motor cables into the wire clamp
retainer at the end of the motor.
Using the 7/16” open end wrench tighten the nut securing the
drive motor cables in the wire clamp retainer.
Secure the drive motor cables to the drive motor housing
with a wire tie
Attach the ferrite removed in step 7D around the two drive
motor cables.
Connect the drive motor cables to the lower board. The black
wire connects to A2, The red wire connects to A1 WARNING: Avoid touching lower
board components such as resistors and capacitors.
Secure the drive motor cables to the other cables in the
lower control board with two wire ties.
Secure drive motor plate.
Slowly and carefully raise the drive motor plate.
Using a 1/2” open end
wrench secure the two motor plate bolts and washers removed.
Install drive belt.
Place the Phillips head screwdriver into the square hole
located in the bottom of the idler pulley assembly.
While pushing down on the Phillips head screwdriver
carefully slide the drive belt into the grooves on the drive motor pulley and
front roller. Slowly release tension on the idler pulley assembly.
Ensure that the drive
belt is aligned properly in the grooves on the drive motor pulley and front
roller pulley.
Lower treadmill.
Carefully lower the rear of the treadmill until the back
feet are resting on the ground.
Install motor cover
Place the top motor cover into position.
Using a Phillips head screwdriver tighten the two screws
securing the left motor cover in place. Tighten the two screws securing the
right motor cover.
Test the unit for proper operation.
Connect the treadmill to the power outlet.
The treadmill will lower itself. Wait until the treadmill
resets its elevation to 0%
Operate the unit at all levels to verify proper operation.
