The following test will help to determine if the cause of no resistance on your Stairmaster 4000PT stepper is the console. By performing the following test, the console is eliminated from the electrical circuit. If resistance is present when the test is performed, the console is bad. Paper Clip Trick

1. First UNPLUG YOUR MACHINE from the wall, then disconnect the grey cable from the back of the console.
2. If your cable is a 6-pin round connector or a 9-pin square connector, using a paper clip formed into a "U" shape, insert the ends of the paper clip in the pin sockets #2 and #4. Then you will need to plug the power cord back in and start stepping. You should experience full pedal resistance.
3. If there is still no pedal resistance, UNPLUG YOUR MACHINE from the wall and disconnect the wire from an end of the load resistor so that there is no wire attached to that end. Then plug the power cord back in and perform the paper clip test again. If resistance is present, the load resistor needs replaced. If resistance is not present, either the gray cable or the alternator is bad.

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This video covers general resistance troubleshooting for the Stairmaster 4400CL, 4600CL, and SC916 Steppers.
Tools Needed: Multi Meter, Jumper Wire
Resistance problems could be either mechanical or electrical in nature.
Mechanical problems are easily identified by noise. If a grinding noise is heard while pedaling, this is an indicator the drive hub assembly is having a problem. If a ratcheting sound is heard while pedaling, this is an indicator of a loose belt or a belt that could be coming off.
Once you've eliminated the possible mechanical causes for resistance problems, then it is time to investigate the electrical system.
The easiest test of the electrical system when investigating a resistance problem is to step onto the pedals and access Diagnostics. This is done by pressing Level ^, 6, ENTER. (DIAGNOSTICS will appear in the upper display window.) Press Level Down twice to get to the alternator test. (ALT TEST will appear in the upper display window.) Press ENTER to begin the test. As the video shows, resistance drops out when the test begins. So, if this occurs, press the Level ^ one time. This will turn the field ON. This verifies that voltage is passing from the display through the display cable to the lower control board. This confirms there is good communication between the console and the lower control board and that the voltage is being supplied to the alternator. If resistance is lost during this portion of the test, inspecting the cable should be the first step of action. Look for bent pins, loose connection or crimped wire.
Other components of the electrical system to inspect for resistance problems are the battery, load resistor, speed sensor and alternator.
We'll discuss the battery first. In order to get a proper reading, testing the battery should be done with the pedals in motion. There are 3 different battery readings a person may encounter. A reading of 6 VDC or greater indicates a good battery. A reading below 6 VDC but higher than 4.8 VDC indicates the battery needs charged for 24 hours. A reading below 4.8 VDC indicates your battery is bad and needs replaced. For more information, watch our battery testing video.
If your battery is good, the next item to check is the speed sensor. The speed sensor should be spaced a business card thickness away from the speed disc. If the speed sensor is spaced properly, the function of the speed sensor can be verified by confirming that proper voltage is present. For more speed sensor troubleshooting, watch our video on speed sensor testing and adjustment.
Next to inspect is the load resistor. Load resistor testing is pretty simple. Load resistors are ohm rated, and you want to verify the proper ohms for the load resistor being tested. Load resistors can cause the resistance to come and go. This means you may pedal a few steps and then the pedals will drop or loose resistance. Then, as the load resistor cools down a bit, you may get resistance again for a few steps. If the resistance goes back and forth like this, the load resistor likely needs replaced. For more information, see our load resistor testing video.
The last electrical component to inspect when investigating a resistance problem is the alternator. The alternator can be easily tested by performing the B+ to Field jumper test. For details on how to perform this test, watch our alternator testing video.



Resistance Troubleshooting Video for Stairmaster Stepper 4400CL 4600CL...

Video about Performing a Stairmaster Alternator Jumper Test

• In today's video, we will be showing you how to verify your Stairmaster alternator is functioning correctly
  
  
  
  
  
  • The quickest way to determine if the alternator is the cause for your resistance issue is by performing what is called a jumper test
  
  
  
  



• To do this test, unplug the power on a PT machine and Stepmill or unhook the battery on a CL (cordless) machine
  
  
  
  
  
  • Power remains disconnected for this test
  
  
  
  



• Remove the right shroud from the unit



• On back of alternator, locate the Field or FLD terminal
  
  
  
  
  
  • This wire is usually brown
  
  
  
  



• Also, locate the terminal labeled Positive or B+
  
  
  
  
  
  • The wire connected to this could be white or black depending on model
  
  
  
  



• Once you've located and disconnected the wires from these terminals, you will need a jumper wire to proceed



• Hook one end of the jumper to the Field terminal and the other end to the B+ or Positive terminal
  
  
  
  
  
  • It is very important that the jumper makes a good connection at both ends
  
  
  
  



• Once you have the jumper connected, proceed to step on the machine
  
  
  
  
  
  • You will have to step fast to keep up for about 10-20 seconds
  
  
  
  



• After stepping on the unit, you will obtain full resistance if the alternator is working properly



• If your alternator passes this test, yet you still have a loss of resistance, you will need to further troubleshoot
  
  
  
  
  
  • Please see our Stairmaster troubleshooting videos
  
  
  
  



• If you do not get resistance, than your alternator is the problem
  
  
  
  
  
  • The common solution is to replace your alternator brushes
    
    
    
    
    
    • First, make sure your jumper wire connection is good
    
    
    
    • If not, you may produce a false negative result
    
    
    
    
  
  
  
  

TEST #5 Moisture Sensor
NOTE: This test is started with the machine completely assembled.This test is performed when an automatic cycle
stops too soon, or runs much longer than expected. NOTE: Dryer will shut down automatically after 2-1/2 hours.
The following items are part of this system: Harness/connection, Metal sensor strips, Machine control electronics
1. Activate the diagnostic test mode and advance past saved fault codes.
2. Open the dryer door. If a continuous beep tone is heard and an alphanumeric number is displayed on the console as soon as the door is opened, a short circuit exists in the moisture sensor system. If this doesn’t happen, go to step 3. Otherwise, go to step 4. NOTE: Over drying may be caused by a short circuit in the sensor system.
3. Locate the two metal sensor strips on the inside of the dryer. Bridge these strips with a wet cloth or finger.
If a continuous beep tone is heard and a software revision number is displayed on the console, the sensor passes the test. Go to step 8. If not, continue with step 4.
4. Access the moisture sensor wires: Remove the lint screen. Remove the two wires holding the lint screen to the top. Remove the four screws from bottom of the duct in rear. Remove the duct from the dryer to access
the moisture sensor.Disconnect the sensor connector.
5. Access the machine control electronics. Remove the connector P13 from the circuit board. Check the main
harness connections between the sensor connector and machine control for a short or open circuit. Replace the main harness if necessary. If the harness is okay, continue with step 6.
6. Measure the resistance across the outermost contacts of the sensor connector that includes the two MOVs. Sensor Harness with MOVs (Metal Oxide Varistors) Sensor Connector Sensor Blower Housing Disconnect sensor connector. If a small resistance is measured, check for debris across moisture strips inside of the drum; clean if debris is present. If debris is not present, replace sensor harness with MOVs. Otherwise go to step 7.
7. Measure the resistance across each of the outermost contacts and the center terminal (ground connection).
If a resistance less than infinity is measured, replace the sensor harness with MOVs.
8. If moisture sensor diagnostic test passes, check the thermistor: Perform TEST #4a. If the problem persists after replacing the moisture sensor, harness with MOVs and thermistor, replace the machine control electronics.

TEST #6 Buttons and Indicators
This test is performed when any of the following situations occurs during the Console Buttons and Indicators Diagnostic Test:
None of the indicators light up No beep sound is heard
Some buttons do not light indicators None of the indicators light up:
1. See Diagnostic Guide/Before Servicing.
2. Perform TEST #1 to verify supply connections.
3. Perform TEST #2.
4. Visually check that the P5 connector is inserted all the way into the machine control electronics.
5. Visually check the user interface assembly connections.
6. If both visual checks pass, replace the user interface assembly.
7. Plug in dryer or reconnect power.
8. Perform the Console Buttons and Indicators Diagnostic test to verify repair.
9. If indicators still do not light, the machine control electronics has failed: Unplug dryer or disconnect power.
Replace the machine control electronics. Plug in dryer or reconnect power. Perform the Console Buttons and Indicators Diagnostic test to verify repair.
No beep sound is heard:
1. Visually check that the P5 connector is inserted all the way into the machine control electronics. If visual check passes, replace the user interface assembly.
2. Plug in dryer or reconnect power.
3. Perform the Console Buttons and Indicators Diagnostic test to verify repair.
4. If replacing the user interface assembly failed: Unplug dryer or disconnect power. Replace the machine control electronics. Plug in dryer or reconnect power. Perform the Console Buttons and Indicators Diagnostic test to verify repair.
Some buttons do not light indicators:
1. Visually check the user interface assembly connections. If visual check passes, replace the user interface assembly.
2. Plug in dryer or reconnect power.
3. Perform the Console Buttons and Indicators Diagnostics test to verify repair.

TEST #7 Door Switch
Activate the diagnostic test mode and perform the Door Switch Diagnostic test.
Functionality is verified with a beep each time the door is closed and opened, and a number and letter appears in the display (i.e., 0E, 09). If any of the above conditions are not met: Unplug dryer or disconnect power.
Check that the wires between the door switch and machine control electronics are connected. If the connections are OK, replace the door switch assembly and retest. If the door switch assembly has been replaced and dryer still does not start, replace the machine control electronics.