True Fitness 500U User manual

True Fitness Service
Manual
Exercise Bicycles
500R, 500U
600R, 600U
750R, 750U
True fitness technology, Inc. makes no representations or warranties regarding the
contents of this manual. We reserve the right to revise this document at any time or
to make changes to the product described within it without notice or obligation to
notify any person of such revisions or changes.
© 2004, True Fitness, Inc. All rights reserved. Printed in the United States of
America.
865 Hoff Road. O’Fallon, MO 63366. 1-800-426-6570. Fax [phone].
www.truefitness.com Revision 9/2004

Recommended Tool List
Technicians will need at minimum the tools listed below to work on the True Fitness
equipment covered by these procedures.
Electrical Tools
A multi meter capable of testing voltage, amperage, resistance and continuity.
Outlet tester with a grounding indicator.
Wire stripper, cutter and crimper.
Flashlight
Mechanical Tools
Screwdrivers:
#1 Phillips, #2 Phillips, large flat blade, small flat blade, short handled flat blade.
Metric hex-key (Allen wrench) set.
Metric socket set and ratchet with 6mm to 19mm sizes and 21mm and 34mm sizes.
Metric combination wrenches with 4mm to 21mm sizes and a 27mm El crank.
Snap ring pliers, both internal and external.
Rubber mallet.
Channel lock pliers or standard pliers with a jaw opening of 2 9/16” for use in removing
and tightening sleeve nuts.
Needle nose pliers.
Crescent wrench
Special Tool
Bicycle crank puller
Park Tool USA CCP-2

True Fitness Bicycle
Service Manual
START
Symptom guide
Wiring Diagrams
Parts Manual
Removal and Replacement Procedures
Page 1

Test Mode *750 ONLY Procedure
D
I
A
G
N
O
S
T
I
C
S
To Enter Diagnostic
Mode
Console / Display
Output
RPM
Console Key Input
Contact Heart Rate
DA (Resistance)
Exit Diagnostics
•
Press and hold the “Start” key as you
begin pedaling.
•Continue pedaling throughout the test.
-------
•Press “Enter” key – initiates the second
LED function test.
•Press “Enter” key again –all LED’s
should be on.
--------
•Press “Enter” key – RPM’s displayed in
the far right window.
--------
•Press “Enter” key –A beep should sound
when each key is pressed.
--------
•Press “Enter” key. Hold both handle
pick-ups. Heart symbol will flash and
readout will display.
-------
•Press “Enter” key – Press + to increase
resistance and – to decrease resistance.
•To quit diagnostics press “Enter” key or
stop pedaling and the unit will reset.
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 2

SYMPTOM GUIDE
500U, 500R
ECB Malfunction . . . . . . . . . . . . . . . . . . . . . . . Page 4
Irregular or No Display . . . . . . . . . . . . . . . . . . Page 5
No RPM Reading . . . . . . . . . . . . . . . . . . . . . . . . Page 6
No Polar Heart Rate . . . . . . . . . . . . . . . . . . . . . . Page 7
600U, 600R
Irregular or No Display . . . . . . . . . . . . . . . . . . . Page 8
No RPM Reading . . . . . . . . . . . . . . . . . . . . . . . . Page 9
No Contact Heart Rate . . . . . . . . . . . . . . . . . . . . Page 10
Handle Bar Buttons
Do Not Function . . . . . . . . . . . . . . . . . . . . . . . . . Page 11
750U, 750R
No Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12
Heavy Resistance . . . . . . . . . . . . . . . . . . . . . . . . . Page 13
Irregular or No Display . . . . . . . . . . . . . . . . . . . Page 14
No Contact Heart Rate . . . . . . . . . . . . . . . . . . . . Page 15
No Polar Heart Rate . . . . . . . . . . . . . . . . . . . . . . Page 16
Page 3

Note: If motor has been bound and then
freed the motor may have been weakened. If
components now move freely but the motor
is laborin
g
–
re
p
lace the motor.
Symptom Probable Cause Corrective Action
ECB
MALFUNCTION
500R, 500U
Control Panel
Defective Cables
Defective ECB
Control Board
Optical Sensor
DC Motor
ECB Limit Switch
Loud Continuous
Tone from lower
board (ECB board)
•
Power on unit. Check for 5VDC between pins 1 and 2. (Page 18)
•No 5VDC? Replace control panel.
•Check for 6VDC or more between pins 5 and 6 of 6PA while issuing
a resistance command.
•No 6VDC or more? Replace control panel.
--------
•Perform continuity check on upper section and lower section cables.
•Replace broken cables.
--------
•If cables test OK and voltage is correct on 5 &6 pins – replace ECB
board
•If ECB does not fix- connect 6PA and 6PB.
--------
•Check DC volts between pins 2 and 3. Rotate blades of the motor
shaft, voltage should shift from 0 VDC and 5VDC. If voltage does
not shift- replace EC B Board
•Check for 6 VDC or more between pins 5&6 on 6 pin PBA @ ECB
board connection. If >6 VDC exists but motor doesn’t rotate, replace
motor.
--------
•Check continuity between pins 2 and 4 of 6PB. Press lower limit
switch.
•If no continuity shift- replace ECB limit switch assembly.
---------
•The loud continuous tone is a safety feature designed to protect the
ECB motor. If the motor binds and cannot move the ECB board will
divert the power from the motor to a speaker that emits this tone. If
you have the continuous tone check to see if the motor is bound.
Check the front pivot point for the magnet bar and loosen the
bolt to allow for the motor to freely move the magnet bar.
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 4

Symptom Probable Cause Corrective Action Recommended Tools
IRREGULAR OR
NO DISPLAY
500R, 500U
DC Adaptor
Adapter Plug or
Jack
Control Panel
Cables
•Connect DC Adapter to 110 VAC power
supply.
•Look for printed output on adapters
label. If greater than 9 VDC computer
board may be damaged.
•Test for 9VDC output. If not 9 VDC
then replace adaptor.
--------
•Connect DC plug to Bike. Does it seat
into the socket properly? If not- replace
adapter or jack.
--------
•Check DC voltage between pins 2 and 4
for 9 VDC on 5PB. (Page 18)
•If 9 VDC is found replace the Control
Panel.
--------
•Perform continuity checks on all upper
and lower cables.
•Replace defective cables.
•If cables OK- replace DC Jack.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone] Page 5

Symptom Probable Cause Corrective Action Recommended Tools
NO RPM
READING
500R, 500U
Control Panel/ RPM
Sensor
Defective Cables
Defective RPM
Sensor Set
•Disconnect 5PA from 5PB. Set meter to
check continuity between 2 and 5 of
5PB. (See Page 18)
•Turn pedals slowly, check continuity
between 2 and 5 of 5PB.
•Does continuity change from off to on?
•If yes – cables and sensor are good –
Replace Control Panel.
•If no – Go to Defective RPM Set.
When the sensor is over the
pickup, continuity will exist.
When sensor is not over pickup,
cicuit will be open.
--------
•Perform continuity checks on all upper
and lower cables.
•Replace defective cables.
--------
•If cables OK- Replace RPM sensor set.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 6

Symptom Probable Cause Corrective Action Recommended Tools
NO POLAR
HEART RATE
500R, 500U
Control Panel
Heart Rate Chest
Strap
External
Interference
•Attach a known good heart rate
transmitter around chest or use polar
simulator.
•If control panel does not display a heart
rate – replace Control Panel.
--------
•If heart rate registers with use of HR
simulator but not chest strap – replace
chest strap.
--------
•If erroneous readings continue, check
for and eliminate external interference.
•Locate RF sources and use process of
elimination. Common sources of RF
interference are: Invisible fences for
pets; wireless networks; cordless
phones, Cell phones, radios, home
security sensors, etc.
Heart Rate Simulator
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone] Page 7

Symptom Probable Cause Corrective Action Recommended Tools
IRREGULAR OR
NO DISPLAY
600R, 600U
Control Panel
Control Board
Cables
AC Voltage Output
Generator Output
Cable
•Probe leads between pin 1 and 2 of 5PB.
(Page 19-20)
•Pedal unit up to at least 30 RPM.
•Is voltage 5 VDC?
•If not 5 VDC – replace Control Panel.
--------
•Disconnect 6PG from 6PH.
•Pedal.
•Check DC voltage between pins 2 and 3
for 5 VDC.
•No 5 VDC? – Replace Control Board.
-------
•Perform continuity checks on all upper
and lower cables.
•Replace defective cables
--------
•Check for AC Voltage between pins 1
and 2 of 3PB, and pins 2 and 3 of 3PB.
•Is there AC voltage output in both
places?
•If yes – replace Control Board.
•Check for AC Voltage between pins 1
and 2 of 3PD, and pins 2 and 3 of 3PD.
•Is there AC voltage output in both
places?
•If no – replace Generator.
------
•Perform a continuity check on the
generator output cable.
•If no continuity – replace cable
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 8

Symptom Probable Cause Corrective Action Recommended Tools
NO RPM
READING
600R, 600U
Control Panel
Defective Cables
Defective RPM
Sensor Set
•Disconnect 5PA from 5PB. (Page 19-
20).
•Set meter to check continuity between
pins 2 and 5 of 5PB
•Turn crank and align the magnet with
the sensor
•Is there continuity? If Yes – Replace
Control Panel. If No- continue to next
step.
--------
•Check continuity of RPM Sensor, when
magnet is in alignment with the sensor
there should be continuity, when not
aligned- no continuity. If it does not
respond properly- replace the sensor.
•Check gap on RPM Sensor
•Perform a continuity check on all upper
and lower cables.
•No continuity? – Replace defective
cable.
•Continuity? – Replace RPM Sensor Set.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone] Page 9

Symptom Probable Cause Corrective Action Recommended Tools
NO CONTACT
HEART RATE
600R, 600U
Control Panel
Defective Cables
Defective Handles
•Disconnect 7P6A and 7P6B from
control panel. 600U (Page 19) 600R
(Page 20). Check continuity between
7P6B and handle mounted heart rate
sensor plates of the following:
HRRR and pin 6 of 7P6B
HRRL and pin 5 of 7P6B
HRLR and pin 2 of 7P6B
HRLL and pin 1 of 7P6B
•Is there continuity?
•If yes – replace computer.
•If No- continue to the next step
--------
•Perform a contact and continuity check
on cable 600 12P, 600 12P coils upper
cables and the handle cables.
•Are cables OK? If No- Replace
defective cables. If Yes- continue on to
the next step.
--------
•Remove and carefully check all
connections to the contact plates.
•Reconnect loose connections.
•If connections OK – Replace handles.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 10

Symptom Probable Cause Corrective Action Recommended Tools
HANDLEBAR
BUTTONS DO
NOT FUNCTION
600R
“Cruise Control”
“Start” Button
“Shift” Button
“_“ Button
“Select” Button
“+” Button
•Remove console-mounting screws.
Locate 10P7B (Page 20).
•Check for continuity between pin 7 and
pin 1 at 10P7B. Press Cruise control
button.
(A)
•No continuity? Perform a continuity
check on the appropriate cable.
•Replace cable or if cable good – replace
handlebar assembly.
--------
•Check for continuity between pin 7 and
pin 2 at 10P7B. Press Start button. See
(A) above.
--------
•Check for continuity between pin 7 and
pin 3 at 10P7B. Press Shift button. See
(A) above.
--------
•Check for continuity between pin 7 and
pin 4 at 10P7B. Press _ button. See (A)
above.
--------
•Check for continuity between pin 7 and
pin 5 at 10P7B. Press Select button. See
(A) above.
--------
•Check for continuity between pin 7 and
pin 6 at 10P7B. Press + button. See (A)
above.
--------
•If all have continuity and problem
persists – replace Console
Multi-meter
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Symptom Probable Cause Corrective Action Recommended Tools
NO RESISTANCE
750U, 750R Console Set
Defective Cables
Power Resistance
Brake Harness/
Lower Board
•
Remove console bolts to access 7-pin
connector. Do not disconnect console
set.
•Enter DA (resistance) test mode.
(Page 2).
•Press + key to force .7 VDC out of
panel.
•Set meter for DC Volts. Measure
between #2 pin and #4 pin at 7- pin
connector.
•Is .7 VDC present? No- replace console
set. If present, continue on.
--------
•Remove right mast cover and handlebar.
•Measure between the #2and #4 wires at
the 7 –pin connector on the lower board.
•Is .7 VDC present? No- replace cable
for console. If present, continue on.
--------
•DO NOT PEDAL.
•Set meter for resistance. Disconnect 3-
pin connector at the lower control board.
Measure resistance between #1 pin and
#3 pin.
•Resistance should be 10 ohms, +/- 1
ohm.
•If less than 10 Ohms- replace power
resistance. If resistance checks OK,
continue on.
--------
•DO NOT PEDAL.
•Remove main body cover, set meter for
continuity.
•Disconnect brake cable from brake and
lower board.
•Check continuity of all wires in cable.
•Check for cross continuity- this would
indicate multiple shorts in the cable.
•No continuity? Replace Brake cable.
•Yes continuity? Replace lower board.
Note:
You must pedal at least
30 RPM when
p
erforming any voltage
test. You may require the
assistance of another
p
erson when performing
volta
g
e checks.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 12

Symptom Probable Cause Corrective Action Recommended Tools
HEAVY
RESISTANCE
750U, 750R
Console Set
Defective Cables
Lower control
Board/Brake
•Remove the console set.
•Disconnect the 7 pin connector from the
back of the console set.
•Pedal.
•Resistance normal? Replace console set.
--------
•Remove pedal and if 3 piece crank
remove crank arm.
•Remove right side cover assembly.
•Disconnect 7- pin connector from the
lower control board.
•Pedal.
•If resistance is normal- replace cable for
console.
--------
•Disconnect 3- pin connector from the
brake.
•Resistance still heavy- Replace brake.
•Resistance normal
•Check brake cables for cross continuity.
•Replace lower control board.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone] Page 13

Symptom Probable Cause Corrective Action Recommended Tools
No Display
750U, 750R Console Set
Brake
Defective Cable
Console Cable/
Lower Control
Board
•Remove console set bolts. Verify good
connection at the back of the console
set. Set meter for DC volts
•Pedal.
•Measure between #1 and #4 wires (Page
21) for 5.5 – 7.5 VDC.
•Is required voltage present?
•If yes- replace console set. If not,
continue on. --------
•Remove pedal and if 3 piece crank
remove crank arm.
•Remove right side cover.
•Disconnect 3- wire connector at brake.
•Set meter for AC volts.
•Pedal.
•The voltage should increase as pedaling
increases.
•Is minimum voltage 9 VAC @ 30
RPM?
•If No- replace Brake. If yes, continue
on.
--------
•Remove pedal and if 3 piece crank
remove crank arm.
•Remove right side cover.
•Disconnect 3- wire cable from brake and
lower control board.
•Set meter for continuity.
•Check all 3 wires in cable for continuity.
•No continuity? Replace cable
----------
•Set meter for DC volts. Reconnect
cable to brake and lower control board.
•Pedal.
•Measure for 5.5 – 7.5 VDC between #1
and #4 wires on 7- pin cable for the
console at the lower control board.
•Voltage is present? Replace cable for
console.
•Voltage not present? Replace lower
control board.
Note:
You must pedal at least
30 RPM when
p
erforming any voltage
test. You may require the
assistance of another
p
erson when performing
volta
g
e checks.
Multi-meter
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 14

Symptom Probable Cause Corrective Action Recommended Tools
NO CONTACT
HEART RATE
750U, 750R
Dirty Sensors
Console Set/
Wiring
Wire Connections
•Verify hand pulse sensors are clean.
--------
•Set meter for continuity.
•Remove Console set.
•Check for continuity in both sets of
hand pulse sensors between the console
set and hand pulse sensor plates.
•If continuity is OK – Replace Console
set. If no- continue on.
--------
•Check wire connections @ handlebar
console mast joint
•Check connections of wires to hand
pulse sensor by removing hand pulse
sensor plates.
•To remove hand pulse sensor plates
carefully pry under one end to free them
from the plastic handgrips.
•Bad connections? - Reconnect/ Replace
bad wires.
•Recheck continuity.
Note:
You must pedal at least
30 RPM when
p
erforming any voltage
test. You may require the
assistance of another
p
erson when performing
volta
g
e checks.
Multi-meter
Double sided tape
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone] Page 15

Symptom Probable Cause Corrective Action Recommended Tools
NO POLAR
HEART RATE
750U, 750R
Control Panel
Defective Cables
Defective ECB
Control Board
•Attach known good heart rate
transmitter around chest or use Polar
simulator.
•Do not touch the hand pulse sensors.
•Start pedaling
•Check display for heart rate.
--------
•Does console display heart rate with
chest strap?
•Does console display heart rate with HR
simulator?
•If unit responds with simulator and not
chest strap then replace chest strap.
•If unit does not respond with strap or
simulator then replace Console set.
Note:
You must pedal at least
30 RPM when
p
erforming any voltage
test. You may require the
assistance of another
p
erson when performing
volta
g
e checks.
Polar Heart Rate
Simulator
Support Services 800-883-8783 Mon-Fri 8:30am-5:00pm Central Time Zone Fax: [phone]
Page 16

WIRING DIAGRAMS
TR / TU 500 Page 18
600 U Page 19
600 R Page 20
TR/TU 750 Page 21
Page 17

Page 18
TR/ TU 500 WIRING DIAGRAM