Horizon Fitness RST 5.6 User manual

2007 Sears
Treadmill Service Manual
Horizon Fitness
Models
RST 5.6
RCT 7.6

Elevation Troubleshooting
No Motor Movement Troubleshooting
Erratic Speed Troubleshooting
Auto Calibration Troubleshooting
Console/Upper Board Troubleshooting
Membrane Keypad Overlay Troubleshooting
Safety Key/Reed Switch Troubleshooting
Heart Rate Troubleshooting
Circuit Breaker Troubleshooting
Engineering Mode
Digital Drive Wiring
RST 5.6 Upper Board
RCT 7.6 Upper Board
Power Source Wiring Diagram
No Motor Movement Voltage Check Points
Cut Console Cable Voltage Chart
Incline Wire Voltage Chart
Reseting The Incline Motor
Lubrication Procedure
3
4
5
7
8
10
11
12
14
15
17
18
19
20
21
23
25
26
27
Table Of Contents

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 3
RST5.6 & RCT 7.6 Sears Service Manual 2007
No Motot Movement TroubleshootingElevation Troubleshooting
Elevation motor starts
running as soon as the power is
turned on. Constant down.
Elevation motor bobs up and down
with command.
Elevation motor does not reach
minimum or maximum settings.
Elevation is stuck down and does
not function. Console is responsive
to the buttons being pressed.
Elevation is stuck at the highest
position and is will not come down.
Console is responsive to the but-
tons being pressed.
Elevation inclines to the high-
est position as soon as power is
applied.
The incline will go up, but not
down. (very rare)
Failed lower board.
Failed elevation motor.
Failed elevation motor.
Failed console cable.
Failed elevation motor.
Failed upper board
Failed upper board, lower board
(very rare for models made after
2003), console cable, and elevation
motor.
Failed lower board
Failed lower board
-Turn on power. Do not press start.
Wait 30-60 seconds and see if
motor is hot. Use caution. Motor can
get very hot.
Referance Incline Voltage Chart.
(p. 25)
-Verify there are no pinches or cuts
on the elevation wires.
-Verify the connections of above
wires.
Referance Incline WVoltage Chart.
(p. 25)
-Verify console cable connections.
Verify there are no pinches or cuts
in the cable.
Referance Console Cable Voltage
Chart. (p. 26)
-Put machine in hardware test
(Eng1) and press start. Eleva-
tion doesn’t respond buttons are
pressed. (You may see a value for
elevation that reads 255 or 1023.
That value will not change when the
buttons are pressed).
Referance Incline Voltage Chart.
(p. 25)
-Put machine in hardware test
(Eng1) and press start. Incline will
work in hardware test only.
Reference Engineering Modes (p.15)
-Verify all wire connections.
-If the incline went into the
highest position without start being
pressed.
-The incline will act normally
when going up, but when the down
incline is pressed there is no
movement.
Replace lower board.
Replace elevation motor.
-Recalibrate elevation motor by
hand. Referance Resetting the
Incline Motor. (p. 25)
-Replace elevation motor.
Replace console cable.
Replace elevation motor.
Replace upper board.
Replace upper board, console
cable, and elevation motor.
Replace lower board.
Replace lower board.
It’s recommended to send console cables for elevation repairs on all models using
sectional console cables.
Symptom Possible Cause Test Procedure Repair

4| rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
No Motor Movement Troubleshooting
4| rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
No Motor Movement Troubleshooting
Symptom Possible Cause Test Procedure Repair
If the AC voltage is missing
or incorrect, check the AC
service or consult an
electrician.
Replace parts as needed.
Replace MCB.
Replace drive motor.
Replace optic sensor.
No Motor Movement - Upon
pressing start, console
responds normally, keys
respond normally, and
elevation works but no belt
movement.
Inadequate power.
Damaged or improper
wiring.
Failed motor control board
(MCB).
Failed drive motor.
Failed optic sensor.
-Check for dedicated circuit
(20 amp is ideal) and check
wall outlet voltage (120 VAC)
Reference Power Source
Wiring Diagram. (p. 20)
-Make sure machine is not
on extension cord or surge
protector.
Reference No Motor
Movement Voltage
Checkpoints. (p. 21)
-Verify there are no pinches or
cuts in the power cord, power
wires motor wires, or console
cable.
-Verify the connections of
above wires and cords.
Reference No Motor
Movement Voltage
Checkpoints. (p. 21)
-Verify power to MCB
Reference No Motor
Movement Voltage
Checkpoints. (p. 21)
-Measure voltage output from
motor.
Reference No Motor
Movement Voltage
Checkpoints. (p. 21)
Reference No Motor
Movement Voltage
Checkpoints. (p. 21)

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 5
RST5.6 & RCT 7.6 Sears Service Manual 2007
Erratic Speed Troubleshooting
Symptom Possible Cause Test Procedure Repair
Erratic speeds - Upon pressing
start, belt speed increases rapidly
and then comes to a complete
stop quickly.
Erratic speeds - Upon pressing
start, belt speed increases rapidly
and does not stop.
Erratic speeds - Running belt
speed is not stable.
Failed optic sensor.
Failed motor control board (MCB).
Machine not calibrated properly.
-Running belt is too loose or too
tight.
-Drive belt is too loose or too
tight.
Inadequate power.
Failed or improper wiring.
Inadequate lubrication on deck
and running belt.
Failed motor control board (MCB).
Reference No Motor Movement
Voltage Checkpoints. (p. 21)
-Run auto calibration.
Reference Engineering Mode.
(p. 15 & p. 16)
-The running belt should not slip
at all when customer is using the
machine
-The drive belt should have
approximately 3/8 of inch
deflection.
-Check for dedicated circuit (20
amp is ideal) and check wall out-
let voltage (120 VAC). Reference
Power Source Wiring Diagram.
(p. 20)
-Make sure machine is not on
extension cord or surge protector.
-Verify there are no pinches or
cuts in the power cord, power
wires motor wires, or console
cable.
-Verify the connections of above
wires and cords.
Reference Cut Console Cable
Voltage Chart. (p. 23 & 24)
-Place hand underneath running
belt and feel for adequate silicone
application.
Reference No Motor Movement
Voltage Check Points. (p. 21)
Replace optic sensor.
Replace MCB.
If unit fails to auto calibrate,
refer to auto calibration
troubleshooting.
-Tighten running belt. Reference
Owners Manual. (p. 14)
-Tighten drive belt
If the AC voltage is missing or
incorrect, check the AC service or
consult an electrician.
Replace parts as needed.
Apply silicone.
Reference Lubrication
Procedure. (p. 27)
Replace MCB.

6| rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Erratic Speed Troubleshooting Continued
Symptom Possible Cause Test Procedure Repair
Erratic Speeds-belt speed
increases without command, but
shows change on display and
beeps.
In a program
Stuck button
-Remove safety key, then replace.
-Start in P1 and see if reoccurs.
-Enter EN90(button test) and test
all buttons. Reference
Engineering Mode. (p. 15 & p.16)
-Remove Upper Control Board.
Check if button works properly
once removed from face plate.
If button does not stick when re-
moved from Upper Control Board,
then replace the face plate.
After removing Uper Control
Board, if button is still stuck,
then replace Upper Control Board.

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 7
RST5.6 & RCT 7.6 Sears Service Manual 2007
Auto Calibration Troubleshooting
Symptom Possible Cause Test Procedure Repair
Failed Auto Calibration – Belt runs
for a few seconds and then stops
and E1 message on console.
Failed Auto Calibration – Belt never
runs and E1 message on console.
Failed Auto Calibration – Board
never sets speeds. Belt will con-
tinue to run and not stop.
Failed RPM sensor.
RPM sensor misaligned.
Failed console cable.
Magnet missing in front roller
pulley.
RPM sensor not aligned properly or
has failed.
Failed motor control board (MCB).
-Put machine into Eng1 and check
for slight fluctuation of speed in
speed window of display. (Speed
should not fluctuate more than a
few hundredths.)
-Adjust sensor bracket to correct
position.
-Check voltage and continuity of
console cable. Reference Cut
Console Cable Voltage Chart. (p.
23 & 24)
- Verify positioning of sensor wire.
(Wire coming from RPM sensor
points toward the front of the unit,
sensor is as close as possible to
the magnet in the pulley without
touching, and the sensor bracket
90-degree angle, not bent in any
way.)
- Put machine into Eng1 and check
for slight fluctuation of speed in
speed window of display. (Speed
should not fluctuate more than a
few hundredths.)
-If other tests mentioned above are
normal then replace MCB.
Replace RPM sensor.
Replace console cable.
Replace magnet.
Reference Troubleshooting for no
motor movement. (p. 4)
Replace RPM sensor.
Replace MCB.

8| rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Console/Upper Board Troubleshooting
Symptom Possible Cause Test Procedure Repair
No display on the console and
power switch on machine is
dark.
No display on the console and
power switch on machine is lit.
Circuit breaker in home has
tripped.
Breaker on machine has tripped
or has failed.
Failed power switch.
Failed power cord.
Improper wiring or AC wires
have failed.
Failed Console cable.
Failed Upper board
-Check for dedicated circuit (20
amp is ideal) and check wall
outlet voltage (120 VAC).
Reference Power Source
Wiring. (p. 20)
-Reset breaker.
Reference Power Source
Wiring. (p. 20)
-Make sure power switch is
turned on.
Reference Power Source
Wiring. (p. 20)
-Take voltage check of power
cord.
Reference Power Source
Wiring. (p. 20)
-Check all wiring coming in from
the power switch to the motor
control board and to the upper
board.
Reference Power Source
Wiring. (p. 20)
Reference Digital Drive Wiring
Diagram. (p. 17)
Reference Upper Board Wiring
Diagrams. (p. 18 & p. 19)
-If LED’s on motor control board
are present, Check console cable
voltages at B7, B8
Reference Cut Console Cable
Voltage Chart. (p. 23 & 24)
-Check voltage and continuity of
console cable.
Reference Cut Console Cable
Voltage Chart. (p. 23 & 24)
Reference Upper Board Wiring
Diagrams. (p. 18 & p. 19)
Reset breaker.
Replace breaker if necessary.
Replace power switch if
necessary.
Replace power cord.
Connect wires correctly or
replace as needed.
Replace console cable.
Replace upper board.

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 9
RST5.6 & RCT 7.6 Sears Service Manual 2007
Console/Upper Board Troubleshooting Continued
Symptom Possible Cause Test Procedure Repair
Running belt stops, console
resets during workout.
Fan Dosent Work at all or is
malfunctioning.
Safety key or reed switch is
positioned incorrectly/ Safety
key is damaged.
Inadequate power.
Damaged or improper wiring.
Inadequate lubrication on
deck and running belt.
Failed Fan or Fan is
disconnected.
-Verify that the safety key
is in position and that it is
secure.
-Check for dedicated circuit
(20 amp is ideal) and check
wall outlet voltage (120 VAC)
Reference Power Source
Wiring Diagram. (p. 20)
-Make sure machine is not
on extension cord or surge
protector.
-Verify there are no pinches or
cuts in the power cord, power
wires motor wires, or console
cable.
-Verify the connections of
above wires and cords
Reference Upper Board
Wiring Diagram.
(p. 18 & p. 19)
Place hand underneath
running belt and feel for
adequate silicone
application.
-Verify fan is seated properly
and not disconnected.
Reference Upper Board
Wiring Diagrams.
(p. 18 & p. 19)
Replace safety key.
If the AC voltage is missing
or incorrect, check the AC
service or consult an
electrician.
Replace parts as needed.
Apply silicone. Reference
Lubrication Procedure.
(p. 27)
If Fan is seated properly,
replace fan.

10 | rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Membrane Key Pad Overlay Troubleshooting
Symptom Possible Cause Test Procedure Repair
All or some of the keys on the
console will not work.
Ribbon cables connecting the
membrane keypad to upper
board are not seated properly or
are disconnected or membrane
keypad is defective.
Upper board or raised tactile
buttons defective.
-Verify the ribbon cables are
connected securely into the
upper board.
Reference Upper Board Wiring
Diagram (User 1 & 2
Connections) (p. 18 & p. 19)
-Keys are pressed and there are
corresponding beeps, but
console does not respond.
(Sometime the key will not
beep until it is released.)
Remove and reseat cables.
Replace upper board.

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 11
RST5.6 & RCT 7.6 Sears Service Manual 2007
Safety Key/Reed Switch Troubleshooting
Symptom Possible Cause Test Procedure Repair
Console only displays dashes in
the display window – Magnet
style key.
Safety key is positioned
incorrectly or has failed.
Failed reed switch.
-Remove safety key and reapply.
-Test magnet.
-Short the switch connector on
the upper board by using a flat
blade screwdriver or by placing
a jumper switch on the
connector.
Reference Upper Board Wiring
Diagram. (p. 18 & p. 19)
Replace safety key.
If the upper board still displays
dashes then replace upper
board. Otherwise replace reed
switch.

12 | rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Heart Rate Troubleshooting
Symptom Possible Cause Test Procedure Repair
Heart rate erratic or no heart
rate function. (Hand Grips)
User error.
Failed heart rate grips.
Failed heart rate receiver.
Reference (p. 13)
Reference (p. 13)
Reference (p.13)
If there is absolutely no heart
response, replace heart rate
grips.
If proper heart rate
instructions are followed and
heart rate continues to be
erratic, replace upper control
board.

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 13
RST5.6 & RCT 7.6 Sears Service Manual 2007
Heart Rate Troubleshooting
Heart Rate Troubleshooting
Problem: There is no heart rate reading.
Solution: Remove the console and verify that the heart rate cables are attached properly, not damaged, cut or pinched, making
sure that the cables are securely inserted into the console.
Check your exercise environment for sources of interference such as large motors from other appliances, security/intercom sys-
tems, fluorescent lights, cordless phone, etc.
You may experience an erratic Heart Rate readout under the following conditions:
• Gripping the heart rate handlebars too tight. Try to maintain moderate pressure while holding onto the heart rate
handlebars.
• Constant movement and vibration due to constantly holding the heart rate grips while exercising, try stopping your
workout while taking pulse.
• When you are breathing heavily during a workout.
• When your hands are constricted by wearing a ring.
• When your hands are dry or cold. Try moistening your palms or rubbing them together to warm.
• Anyone with heavy arrhythmia.
• Anyone with arteriosclerosis or peripheral circulation disorder.
• Anyone whose skin on the measuring palms is especially thick.
NOTE: Outside interference sources such as computers, motors and fluorescent lights may cause the heart rate reading to be
erratic.
Proper use instructions
Handlebars
Place the palm of your hands directly on the grip pulse handlebars. Both hands must grip the bars for your heart rate to register.
It takes 5 consecutive heart beats (15-20 seconds) for your heart rate to register. When gripping the pulse handlebars, do not
grip tightly. Holding the grips tightly may elevate your blood pressure. Keep a loose, cupping hold. You may experience an erratic
readout if consistently holding the grip pulse handlebars. Make sure to clean the pulse sensors to ensure proper contact can be
maintained.

14 | rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Circuit Breaker Troubleshooting
Symptom Possible Cause Test Procedure Repair
Machine will trip home circuit
breaker.
Machine breaker will trip.
Inadequate power.
Inadequate lubrication on
deck and running belt.
Failed running belt.
Failed drive motor.
Failed motor control board
(MCB).
Failed circuit breaker
-Check for dedicated circuit
(20 amp is ideal) and check
wall outlet voltage. (120 VAC)
Reference Power Source
Wiring Diagram. (p. 20)
-Make sure machine is not
on extension cord or surge
protector.
-Place hand underneath
running belt and feel for
adequate silicone
application.
-Feel underside of running
belt. It should have a rough
feel to it. (similar to denim or
canvas.)
-Perform AMP draw test on
motor.
Reference No Motor
Movement Voltage Check.
(p. 21)
Reference No Motor
Movement Voltage Check.
(p. 21)
Reference Power Source
Wiring Diagram. (p. 20)
If the AC voltage is missing
or incorrect, check the AC
service or consult an
electrician.
Apply Silicon lubrication.
Reference Lubrication
Procedure. (p. 27)
Replace running belt.
Replace drive motor.
Replace MCB.
Replace circuit breaker.

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 15
RST5.6 & RCT 7.6 Sears Service Manual 2007
Engineering Mode
Treadmill Engineering Menu Definition
General
• Hold Incline + and Speed - for 3 seconds
• Speed +/- navigates once entered
• Enter Selects modes
• Hold Stop for three seconds to exit modes
• Defaults to Eng0
• Defaults to scrolling “ENGINEERING MENU”
o Will scroll “DISPLAY TEST” if navigated back to Eng0
Eng0 (Display Test)
• The information portion of the display will show “Eng0”
• The matrix will scroll “DISPLAY TEST”
• When selected, all display segments should be on
• When pressed, each button will beep and have a unique display change
o Stop turn all display segments off
o Start turns all display segments on
o If there is scrolling speed and incline, the display will scroll the speed or incline when the quick keys are pressed
Eng1 (Hardware Test)
• The information portion of the display will show “Eng1”
• The matrix will scroll “HARDWARE TEST”
• After entered, press Start to begin
Eng2 (Auto Calibration)
• The information portion of the display will show “Eng2”
• The matrix will scroll “AUTO CALIBRATE”
• After entered, press Start to begin
• There should be no excessive speed overshoot
• The Engineering Menu will be exited upon successful completion
Eng3 (Switch Function)
• The information portion of the display will show “Eng3”
• The matrix will scroll “SWITCH FUNCTION”
• Start selects miles or km
o The display will show “0” for miles or “1” for km
o The display will scroll “MILES” or “KM” when Start is pressed to change
o The new setting is automatically saved when Start is pressed, no other buttons need to be pressed to save
• Enter changes the model, if applicable
o The new setting is automatically saved

16 | rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Engineering Mode Continued
• If the treadmill has a Demo Mode then Eng3 will also have the following:
(T73, T74, 2.3T, 3.3T, 5.3T T4, T6, LS925T, RCT7.6, 30519, 620T, 720T, 730T, 820T, 830T, 930T)
o The Brickyard will scroll “DEMO ON” or “DEMO OFF”.
o The default will be “DEMO ON”.
o The +/- buttons will change between the Demo On and Demo Off settings.
o The mile/ km will continue to function as normal.
Eng4 (Information)
• The information portion of the display will show “Eng4”
• The matrix will scroll “INFORMATION”
• Once entered, the display will scroll “ACCUMULATED TIME”
o “F00” will appear in the information portion of the display along with the accumulated time
• Speed or Incline +/- will switch between the accumulated time and distance
• When changed , the display will scroll “ACCUMULATED DISTANCE”
o “F01” will appear in the information portion of the display along with the accumulated distance in miles or km de-
pending upon current setting
Note 1: There should be no Manual Calibration. This function is not needed
Note 2: There should be no Roller Diameter Value set up. This should be done internal to the software. If there are multiple
models included in one software package, the program should automatically adjust the roller diameter value. There is no need
for the user to change.

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 17
RST5.6 & RCT 7.6 Sears Service Manual 2007
Digital Drive Wiring Diagram
MCB
WHITE
BLACK
BLACK
RED
WHITE
BLACK
WHITE
GREEN
Power Cord 110-120 VAC
GREEN
+2.5vdc
EL - Vcc (+2.5v)
EL - Pot
Gnd
Digital Ground
RPM
Power Voltage (+15V)
Power Voltage (+15V)
Speed Command pwr
RELAY
DOWN Incline
UP Incline
Optic Speed Sensor
Speed Sensor
BLACK +GND
WHITE PULSE
RED +5V
BLUE GND
BLACK GND
GREEN
Drive Motor 0-90 VDC
BLACK
RED
BREAKER
Digital Ground
EL. Pol
EL. GND
Incline Motor

18 | rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
RST 5.6 Upper Board
KM
MILE
SMI
User 2 User 1
Console
Cable
Safety Key Shaft Signal
Interface
HR Grip
Receiver
LCD Floating Display Connection
Heart Rate Reciever

rst 5.6 & rct 7.6 service manual 2007_rev1.0 | 19
RST5.6 & RCT 7.6 Sears Service Manual 2007
RCT 7.6 Upper Board
KM
MILE
SMI
USER 2
USER 1
Fan Connection
LED Floating Display Connection
Elevation
Up and Down
USER 2 Key USER 1Key
Speed
Up and Down
Safety Key
Console
Cable
Heart Rate Reciever

20 | rst 5.6 & rct 7.6 service manual 2007_rev1.0
RST5.6 & RCT 7.6 Sears Service Manual 2007
Power Source Wiring Diagram
ABC
SOCKET
ON/OFF
SWITCH BREAKER
DE
AFCF
To Motor Control Board
A – Socket wire to breaker or on/off switch.
B – Ground
C – Socket wire to breaker or on/off switch.
D – On/Off switch to motor control board.
E – On/Off switch to motor control board.
F – On/Off switch to breaker.
Note: (Wires A & C are interchangeable.)
Wire length will determine connection point.
Wire length will determine connection point.