Staircase Has Resistance But Is Choppy During Exercise; Troubleshooting Notes - Stairmaster 8G Gauntlet Service Manual

Staircase has Resistance but is Choppy During Exercise

Use these instructions if you have already cleared a mechanical inspection for parts interfering with the steps. Generally,
the issue with choppy/sticking steps is more commonly traced to a physical issue rather than an electrical one.
1. Inspect Main Cable for Corrosion at all connections.
2. Check alternator brush length.
a. Remove user-right side cover
b. Remove brown wire from W3 (FLD BRN) post of alternator.
c. Loosen ¼" bolts on W3 post.
d. Remove and verify brush length and quality. We recommend replacing brushes that are ¼" or less.
3. Check Load Resistor for a reading of 0.5 to 0.6 Ohms (Ω). If lower than 0.5 Ohms, then replace the load resistor
(SM24989).
4. If load resistor checks good, replace the alternator brushes (SM24557) if worn or the alternator (SM22900).

Troubleshooting Notes

• If you suspect the alternator, disconnect all the wires and check the resistance across the field terminal and the
alternator housing; a typical Alternator should read around 4 Ohms or higher.
• The Field LED on the relay board will flicker at higher speed levels. This is the PWM signal from the console to
the field terminal of the alternator to control resistance / speed. If you experience full resistance through all
levels and the field light doesn't flicker; replace the console.
• To verify that the load resistor is working correctly, you must ohm the resistor out using your multi meter. The
load resistor must read above 0.5 Ohms. If the resistor reads anything less than 0.5 Ohms, then replace the load
resistor (SM24989).
• Always perform mechanical troubleshooting in addition to electrical trouble shooting for resistance problems.
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