Precor C556 User manual

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C556 Elliptical Fitness Crosstrainer
Warning: This service manual is for use by Precor trained service providers only.
IfyouarenotaPrecorTrainedServicer,youmustnotattempttoserviceanyPrecorProduct;
Call your dealer for service.
This document contains information required to perform the majority of troubleshooting, and
replacement procedures required to repair and maintain this product.
This document contains general product information, software diagnostic procedures (when
available), preventative maintenance procedures, inspection and adjustment procedures,
troubleshooting procedures, replacement procedures and electrical block and wiring diagrams.
To move directly to a procedure, click the appropriate procedure in the bookmark section to the
left of this page. You may “drag” the separator bar between this page and the bookmark section
to change the size of the page being viewed.
© 2003 Precor Incorporated
Unauthorized Reproduction and Distribution Prohibited By Law

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Section One - Things You Should Know
C556 Serial Codes and Manufacturing Dates
The C556 has been manufactured in two versions. The applicable serial codes and
manufacturing dates associated with each version will be detailed below. When servicing a C556
it is critical that you are aware of which version of C556 you are servicing. The differences in the
versions may greatly impact service requirements and procedures. For convenience, the
versions detailed below will be referred to as version 1 or version 2 in the reminder of this service
manual. Any procedures that do not reference a specific version is applicable to all versions of
the C556.
Version 1 was manufactured between May 2000 and July 2001. The serial codes associated
with version 1 are 6Q, 70, 8Y, 8Z, AC, AD, AN and BB.
Version 2 was manufactured between July 2001 and the present. The serial codes associated
with version 2 are DA, DB, EW, HD and HE.
Right, Left, Front, and Back Conventions
In this manual, right, left, front, and back are from the perspective of a user standing on the C556,
facing the display enclosure.
Warning and Caution Statements and General Safety Guidelines
Warning statements indicate a particularly dangerous activity. Warning statements you will find in
this manual include:
• To remove power from the EFX, the power cord must be disconnected from the wall outlet.
Always ensure that the EFX is unplugged from the wall outlet when you inspect or adjust the
EFX, or when you isolate, remove, or replace an EFX component.
• Removing the covers exposes high voltage components and potentially dangerous
machinery. Exercise extreme caution when you perform maintenance procedures with the
hood removed.
• During service operations you will be very close to moving machinery and high voltage
components. When you perform maintenance procedures with the covers removed, remove
jewelry (especially from ears and neck), tie up long hair, remove neck ties, and do not wear
loose clothing.
• Exercise caution when touching any wire or electrical component during EFX operation.
• A pinching hazard exists when the unit is operated by turning the crankarms by hand. It is
possible to seriously pinch a finger between the crankarm and stairarm. The stairarms
should be removed before operating the crankarms by hand.

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Caution statements are intended to prevent damage to the EFX as a result of the current activity.
Caution statements included in this manual are listed below:
• When it is necessary to lift or move the EFX, ensure that the EFX has adequate support and
that you use proper lifting techniques.
Safety guidelines you should know and follow include:
• Read the owner’s manual and follow all operating instructions.
• Operate the EFX on a solid, level surface.

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• Visually check the EFX before beginning service or maintenance operations. If it is not
completely assembled or is damaged in any way, exercise extreme caution while operating
and checking the EFX.
• When operating the EFX, do not wear loose clothing. Do not wear shoes with heels or
leather soles. Check the soles of your shoes and remove any embedded stones. Tie long
hair back.
• Do not rock the unit. Do not stand or climb on the handlebars, display enclosure, or cover.
• Do not set anything on the handlebars, display enclosure, or cover. Never place liquids on
any part of the EFX, while performing service.
• To prevent electrical shock, keep all electrical components, such as the power cord and
circuit breaker away from water and other liquids.
• Do not use accessory attachments that are not recommended by the manufacturer-such
attachments might cause injuries.
General Information
For the latest exploded view, part number and part pricing information, visit the Precor dealer
website at “www.precor.com/Dealer”.
Tools Required
Multimeter Allen wrench set
Anti-static kit Screwdriver set
4” - 6” gear puller 1/2” allen key, socket wrench mounted
“C” clamp or Carpenter’s clamp Precor part number 20030-117 belt gauge
US and metric end wrench set Straight edge
US and metric socket wrench set
Torque wrench, 200 in./lbs.
Torque wrench, 200 ft./lbs

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Section Two - Preventive Maintenance
Preventive maintenance measures are either scheduled or unscheduled. Scheduled preventive
maintenance activities are included here so that you are aware of preventive measures
performed on a regular basis.
Regular Preventive Maintenance (Owner)
Cleanliness of the EFX and its operating environment will keep maintenance problems and
service calls to a minimum. Precor recommends that you perform the following preventive
maintenance schedule.
After Each Use
• Turn off and unplug the EFX.
• Wipe down the covers, handlebars, stairarm wheels and stairarm ramps with a damp cloth.
Daily Maintenance
Clean the EFX’s frame, covers, stairarms, stairarm ramps and stairarm wheels using water or
“Simple Green”. Wipe the surface of the electronic console with a damp sponge or soft cloth. Dry
with a clean towel. “Simple Green” is the only cleaning solution that has been tested and
approved for use on the C556 ramps. Use of any other cleaner, may cause degradation of the
ramp anodizing and void the ramp warranty. The use of an acid (citric) based cleaner will cause
ramp anodizing damage and is not authorized by Precor.
Weekly Maintenance
• Vacuum underneath the EFX, following these steps:
1. Turn off the EFX with the circuit breaker, then unplug it from the wall outlet
2. Place the EFX on its side.
Note:
Place a drop cloth under the EFX to protect the flooring and to ensure that the EFX handrail
is not scratched or damaged.
3. Vacuum the rug or damp mop the floor.
4. Make sure that the floor is dry before returning the EFX to an upright position.

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Quarterly Maintenance
1. Remove the rear covers.
2. Check the step up and input belt alignment and tension as in Procedure 5.3.
3. Replace the rear cover.
On-Site Preventive Maintenance (Service Technician)
When you are called to service a EFX, perform these preventive maintenance activities:
• Perform the software diagnostics. Check LED and keypad function. Record the odometer
reading.
• Check speed sensor function (is the stride rate displayed when the unit is in operation?). If
not, see Procedure 6.3
• Visually inspect the drive belts for cracks, fraying or excessive wear.
• Inspect the power cord. If the power cord is damaged, install a new power cord.
• Visually examine all wires and check connectors and wire connections. Secure connections
and replace wiring as necessary.

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Procedure 3.1 - Software Access Codes
The C556 uses the standard access codes to provide access to the various software features. In
using the standardized access codes the keys are hypothetically numbered left to right with key
#1 on the far left and key #7 on the far right. The standard access codes use all sequential key
presses. The allowable delay between key presses is short. If too much time is taken between
key presses the access procedure will be aborted. If the access is aborted, it will be necessary to
start over from the beginning. See Diagram 3.1. The C556 display does not utilize key positions
#2 and #3, however, they must be counted to correctly locate keys #4 through #6. On the C556
display key #1 is the RESET key and key #4 is the QUICK START key.
Standard Access Codes
Diagnostics Keys RESET,5,1,7,6,5,7,6,1
Odometer Keys RESET,6,5
Club Settings Keys RESET,5,6,5,1,5,6,5
Diagram 3.1 - C556 Display Panel

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Procedure 3.2 - Accessing the Diagnostic Program
The EFX diagnostic software cycles through the following tests:
• Display Test
• Keyboard Test
• Heart Rate Test
• Brake (resistance) Test
Procedure
1. Plug the power cord into the wall outlet, then turn on the EFX with the circuit breaker.
2. Press keys RESET,5,1,7,6,5,7,6,1., sequentially.
3. The message DISPLAY TEST will be displayed followed by every LED on the display being
illuminated. Check each LED segment to ensure that all of the segments are illuminated.
Press the ENTER key to advance to the keyboard test.
4. The message KEYBOARD TEST will be displayed followed by a graphical representation of
each key position on the display housing. As each key on the display is pressed the key
representation is turned “off”, indicating that the key is functioning. Check each key in this
manner, including the numeric keyboard. Press and hold the ENTER key for 2 seconds to
advance to the heart rate test.
5. The message HEART RATE TEST will be displayed followed by the unfiltered (U), filtered
(F) and polar (P) heart rate readings if the heart rate option is installed in the C556 and a
chest strap transmitter or a test transmitter is being used. If the heart rate option is not
installed in the C556, the message NO HEART RATE RECEIVER will be displayed instead
of the heart rate readings. Press the ENTER key to advance to the brake test.
6. The message BRAKE TEST will be displayed followed the resistance level and brake level
readings. This test allows you to test the brake (resistance) at each resistance level. Press
the ENTER key to exit the diagnostics program.

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Procedure 3.3 - Displaying the Odometer
Procedure
1. Plug the power cord into the wall outlet, then turn on the EFX with the circuit breaker.
2. With the PRECOR C556 banner scrolling, press keys RESET,6,5, sequentially. The
message ODOMETER will be displayed followed by the total number of strides
accumulated. The total number of strides can be converted to miles by dividing by 2241 or
to kilometers by dividing by 1392.5. Press the ENTER key to advance to total hours.
3. The message HOURS will be displayed followed by the total number of hours that the C556
has been in use. Press the ENTER key to advance to software version.
4. The message SOFTWARE VERSION will be displayed followed by the software versions of
the upper and lower PCA’s. For example, UPPER 1.01 LOWER 1.01. Press the ENTER key
to advance to error log.
5. The message ERROR LOG will be displayed followed by the error in log position 1. Each
log entry shows the log position, the stride count when the error occurred and the hour
meter when the error occurred. For example; 1 ER21 123456 STR 45678 HRS. The error
log can record up to ten error conditions. The error code in position one will be the most
recent error and the error in position ten will be the oldest error. If more than ten errors have
been logged, only the ten most recent will be displayed. When a new error is logged, each
existing error is pushed down one position and the error in position 10, if any, is lost. Use the
▲ and ▼keys to move through the log. Pressing and holding the QUICK START key for
four seconds will clear the log. Press the ENTER key to exit the odometer program.

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Procedure 3.4 - Club Settings
1. Enter the club settings by pressing keys RESET,5,6,5,1,5,6,5, sequentially.
2. The message SELECT LANGUAGE will be displayed followed by the currently selected
language. Use the ▲ and ▼ keys to select the language preference. Press the ENTER
key to advance to units of measurement.
3. The message SELECT UNITS will be displayed followed by the currently selected unit of
measurement. Use the ▲ and ▼ keys to select either U.S. Standard or METRIC
measurements. Press the ENTER key to advance to maximum workout time.
4. The message SET MAX WORKOUT TIME will be displayed followed by the currently
selected maximum workout time. Use the ▲ and ▼ keys to select the maximum workout
time. The maximum workout time may be set between 1 and 240 minutes or no limit. Press
ENTER to advance to maximum pause time.
5. The message SET MAX PAUSE TIME will be displayed followed by the currently selected
maximum pause time. Use the ▲ and ▼ keys to select the maximum pause time. The
maximum pause time is the that will elapse after the pause key has been pressed until the
unit resets. The maximum pause time may be set between 1 and 120 seconds. Press
ENTER to exit the club settings program.

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Procedure 3.5 - Documenting Software Problems
When a problem is found with either the software or upper or lower PCA’s, record the information
listed below. If you isolated the problem to either the PROM, upper PCA, or lower PCA, include
the information you recorded with the malfunctioning PROM or PCA when you ship it to Precor.
When a problem occurs, record the following information:
• Model and serial number
• Software version number
Note:
Look at the PROM mounted on the upper PCA. A label on the PROM indicates the software
version number.
• User and program number running when the problem occurred
• A description of:
a What happened or failed to happen.
b The action taken by the user just before the problem occurred.
c Problem-related information (such as how far into the program the problem occurred,
the work level being used when the problem occurred, etc.).
• The frequency of occurrence.

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Section Four - Checking C556 Operation
This section provides you with a quick method of checking EFX operation. Check the operation
of the EFX at the end of most maintenance procedures.
Procedure
1. Plug the power cord into the wall outlet and set the on/off switch in the “on” position.
2. When the PRECOR C556......WORK OUT SMARTER banner scrolling, press QUICK
START.
3. Select Resistance Level 1 and press ENTER.
4. Operate the EFX for 4–5 minutes. As you operate the EFX, concentrate on the operating
sounds made by the unit. Be on the alert for unusual rubbing, hitting, grinding, or squeaking
noises.
5. If the EFX makes unusual noises or the electronic display does not change appropriately,
troubleshoot per section 6.
6. Press the RESISTANCE ▲ key until you reach Resistance Level 10. Operate the EFX for
another 2–3 minutes.
7. If the EFX resistance does not change or the operation of the EFX feels inconsistent
compared with Resistance Level 1, troubleshoot per section 6.
8. Press the RESISTANCE ▲ key until you reach Resistance Level 20. Operate the EFX for
another 2–3 minutes.
9. If the resistance of the C556 does not change or the EFX operation feels inconsistent with
Resistance Levels 1 and 10, troubleshoot per Procedure 6.5.
10. Check the LED’s mounted on the upper PCA and the function keys displayed on the
electronic console by performing Procedure 3.2.
11. Turn off the EFX with the on/off switch, then unplug the power cord from the wall outlet.

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Procedure 5.1 - Measuring the Resistance of an Eddy Current
Magnet
Caution
Remove power from the EFX before you measure magnet resistance.
Procedure
1. Set the on/off switch in the “off” position, then unplug the power cord from the wall outlet.
WARNING
Before continuing with this procedure, review the Warning and Caution statements listed in
Section One, Things You Should Know.
1. Remove the rear cover as described in Procedure 7.1.
2. Set the ohmmeter to a range that will conveniently read up to 125 Ω.
3. Disconnect the magnet wires. Measure the resistance between the two magnet wires.
Note:
The resistance of the magnets will be higher than optimum (90 - 110 Ω) when they are warm.
4. If the resistance measures significantly less than 90 Ωor significantly more than 110 Ω...
THEN... OTHERWISE...
Replace the magnet as described Reconnect the magnet wires, then
in Procedure 7.13. continue with the next step.
5. Re-install the rear cover as described in Procedure 7.1, then check the operation of the unit
as described in Section Four.

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Procedure 5.2 - Inspecting and Adjusting Belt Alignment and
Tension
Procedure
1. Set the on/off switch in the “off” position, then unplug the power cord from the wall outlet.
WARNING
Before continuing with this procedure, review the Warning and Caution statements listed in
Section One, Things You Should Know.
2. Remove the rear cover as described in Procedure 7.26.
3. Remove both stairarms as described in Procedure 7.16.
4. Operate the unit by rapidly rotating a crankarm by hand. As the unit operates watch the
drive belts for proper alignment. The belts should operate parallel to each other and the
belts should maintain even spacing.
5. If the belts are not correctly aligned...
THEN... OTHERWISE...
Continue with the next step. Skip to step 13
6. Refer to Diagram 5.1 for the following belt alignment steps.The right and left tension bolts
have locking tabs. If necessary, use pliers to bend the locking tabs out of the way so that the
bolts can be turned.
7. If the step up pulley belt is out of alignment to the right, continue with step 9.
8. If the step up pulley belt is out of alignment to the left, continue with step 11.
9. Turn the left tension bolt 1/4 turn clockwise, then repeat step 4. If turning the left adjustment
bolt 1/4 of a turn was not sufficient, turn the right tension bolt 1/4 of a turn counterclockwise.
10. Repeat step 8, alternating between the left and right tension bolts until the alignment is
correct. Continue with step 13.
11. Turn the right tension bolt 1/4 of a turn clockwise, then repeat step 4. If turning the right
adjustment bolt 1/4 of a turn was not sufficient, turn the left tension bolt 1/4 turn
counterclockwise.
12. Repeat step 11, alternating between the right and left tension bolts until the alignment is
correct.

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13. Belt tension must now be checked and if necessary corrected. Remember, if it is necessary
to change the belt tension, the belt alignment must be maintained.
Diagram 5.1 - Drive Unit
14. Place a belt gauge (Precor part # 20030-117 or equivalent) in the middle of the step up belt
and the center of the belt span (see Diagram 5.2). Lay a straight edge along the length of
the belt and beside the belt gauge. Slide one of the o-rings up against the shoulder of the
belt gauge. Press downward on the belt gauge, causing the belt to deflect. Read the
deflection on the belt gauge at the edge of the straight edge. Deflect the belt 1/4”. Read the
tension across the top edge of the o-ring. If the belt is correctly tensioned the gauge will
read between 19 and 21 pounds.
15. If the tension in step 13 is correct skip to step 18. Otherwise continue with the next step.
Input
Pulley
Stub
Tensioner
Step Up
Pulley
Tension Bolt Tension Bolt
Left Right

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Diagram 5.2 - Measuring Belt tension
16. If the locking tabs on the right and left tension bolts have not been straightened, use pliers to
bend the locking tabs out of the way so that the bolts can be turned.
IF... THEN...
The belt tensioning gauge reads Turn both tension bolts
less than 19 pounds clockwise, in equal quarter-turn
increments, until the belt tensioning
gauge reads 19 - 21 pounds @1/4” deflection.
The belt tensioning gauge reads Turn both tension bolts
more than 21 pounds counterclockwise, in equal
quarter-turn increments, until the belt
tensioning gauge reads 19 - 21 pounds @ 1/4”
deflection.
17. Verify that the belt alignment is still correct by performing the procedure in step 4.
18. When both the step pulley tension and alignment are correct, use pliers to bend the tension
bolt locking tabs into the “locking” position.
19. The input pulley tension must now be checked and corrected, if necessary. There is not
sufficient room to use the belt tension gauge to set the input pulley belt tension. It will be
necessary to use the correctly tensioned step up belt as a comparison to set the input belt
tension.
20. Using your finger, press in on the center of the step up pulley belt to get a feeling of how
much pressure it takes to deflect the belt a 1/4”.
20 lbs
1/4”

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21. Using your finger, press in on the center of the lower span of the input belt. Compare the
pressure required to deflect the input belt to the pressure required to deflect the step up belt.
Diagram 5.3 - Stub Tensioner
22. Loosen the stub tensioner axle nut slightly. Turn the stub tensioner adjustment bolt
clockwise to increase or counterclockwise to decrease the input belt tension.
23. When the input belt tension is correct, torque the stub tensioner nut to 200 in/lbs. Replace
the stairarms per Procedure 7.16.
24. Check the operation of the unit as described in Section Four, then re-install the rear cover
as described in Procedure 7.26
Stub
Tensioner
Stub Tensioner
Axle Nut
Stub Tensioner
Adjustment Bolt

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Procedure 6.1 - Troubleshooting the Lower and Upper
Interconnect Cables
Anti-static kits can be ordered from Precor (part number 20024-101).
Troubleshooting the Upper Interconnect Cable
1. Set the on/off switch in the “off” position.
WARNING
Before continuing with this procedure, review the Warning and Caution statements listed in
Section One, Things You Should Know.
2. Attach the anti-static wrist strap to your arm, then connect the ground lead of the wrist strap
to the units frame.
3. Remove two screws that fasten the upper mid-point cover. Remove two screws that fasten
the lower mid-point cover. Remove both halves of the cover and the split gasket. See
Diagram 6.1
Diagram 6.1 - Mid-Point Cover
4. Remove the four screws from the rear of the upper display housing. Remove the display
housing front panel from the display housing. Disconnect the upper interconnect cable from
the upper PCA (connector J5).
Split Ring
Upper Cover
Upper Cover
Mounting Screw
Lower Cover
Lower Cover
Mounting Screw

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5. Disconnect the upper interconnect cable from the mid-point connector. See Diagram 6.2
Diagram 6.2 - Mid-Point Connector
6. External of the upper column, connect a replacement upper interconnect cable to the
mid-point connector and the upper PCA (connector J5).
7. Check operation as described in Section 4. If the unit works properly, replace the upper
interconnect cable as described in Procedure 7.4.
8. If the symptoms are unchanged, remove the external upper interconnect cable. Reconnect
the internal upper interconnect cable to the mid-point connector and the upper PCA. Set the
display housing front panel in it’s mounting position and fasten it with the four mounting
screws removed in step 4. Trouble shoot the lower interconnect cable starting with step 9.
Troubleshooting the Lower Interconnect Cable
9. Remove the rear cover as described in Procedure 7.1. Remove the shield from the lower
PCA.
10. Disconnect the lower interconnect cable from the mid-point connector and the lower PCA
(connector J5).
11. External of the frame, connect a replacement lower interconnect cable to the mid-point
connector and the lower PCA.
12. Check operation as described in Section 4. If the unit works properly, replace the lower
interconnect cable as described in Procedure 7.4.
13. If the symptoms are unchanged, remove the external lower interconnect cable. Reconnect
the internal lower interconnect cable to the mid-point connector and the lower PCA. Remove
the upper and lower interconnect cables from the mid-point connector. Connect a
replacement mid-point connector between the two interconnect cables and retest the unit
per Procedure 4.
14. Replace the lower PCA shield, rear cover (Procedure 7.1) and the main column cover
(Procedure 7.27). If the unit still does function correctly, contact Precor Technical Support.
Mid-Point
Connector
Lower
Interconnect
Cable
Upper
Interconnect
Cable

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Procedure 6.2 - Troubleshooting the Keypad and Upper PCA
If the function keys on the electronic console are unresponsive, the problem may be either the
upper PCA or keypad. The keys on this unit are touch sensitive keys. It is necessary to use the
keypad diagnostics to troubleshoot the key functions.
Procedure
1. Set the on/off switch in the “off” position.
WARNING
Before continuing with this procedure, review the Warning and Caution statements listed in
Section One.
2. Attach the anti-static wrist strap to your arm, then connect the ground lead of the wrist strap
to the units frame.
3. If the EFX powers up and functions normally until a particular key(s) is pressed, skip to step
12.
4. If a “key depressed” message is immediately displayed when the EFX is powered up,
continue with the next step.
5. This condition may be caused by either the keypad or upper PCA. Set the on/off switch in
the “off” position.
6. Remove the four screws that fastens the display housing front panel to the display housing
backing plate. These screws are located on the rear of the display housing backing plate.
7. Lift the display housing front panel off of the display housing backing plate. Remove the
keypad connector from the upper PCA. See Diagram 6.3.