Exercise treadmills · TM family

Cardiac Science TM 55: troubleshooting and error codes

The ServiceForge knowledge base holds 32 documented symptoms for the Cardiac Science TM 55, with 42 ranked causes, 68 diagnostic checks with test points and expected values, and 5 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Building circuit breaker repeatedly trips high voltage

Building circuit breaker trips when treadmill is powered on and continues to trip after reset.

Ranked causes

1. Incorrect outlet voltage rating (occasional)
2. Power cord damaged (occasional)
3. Faulty configuration plate (in-rush limiter) (occasional)

First check

Check outlet voltage

Test point: outlet
Expected: correct rating for treadmill
Tools: voltage meter

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Building circuit breaker trips repeatedly high voltage

Building circuit breaker resets but trips again when treadmill is powered on

Ranked causes

1. Outlet voltage incorrect for treadmill (occasional)
2. Power cord damaged (occasional)
3. Configuration plate faulty (in-rush limiter issue) (occasional)

First check

Measure outlet voltage

Test point: Building power outlet
Expected: Voltage matches treadmill rating specification

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Circuit breaker trips repeatedly high voltage

Building circuit breaker trips when treadmill is powered on or in use

Ranked causes

1. Incorrect outlet or breaker voltage rating (occasional)
2. Power cord is damaged (occasional)
3. Faulty in-rush limiter configuration plate (occasional)

First check

Verify outlet voltage and breaker rating

Test point: Power outlet and building circuit breaker
Expected: Correct rating for treadmill
Tools: Voltmeter

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Transformer primary fuse blown (F1 or F2) high voltage

Fuses F1 or F2 in the transformer primary circuit blow repeatedly or initially

Ranked causes

1. Transformer winding short or overload condition (unknown)
2. Mechanical parts jammed in grade change assembly (occasional)
3. 12 volt power supply failure (occasional)

First check

Measure primary transformer winding continuity

Test point: Transformer primary windings
Expected: 2 ohms or less, <= 2
Tools: Ohmmeter

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit does not start high voltage

Treadmill fails to power on or begin operation

Ranked causes

3. Building circuit breaker tripped (occasional)
6. Fuse in treadmill blown (occasional)
8. Drive board failure on AC Drive Module (rare)

First check

Verify treadmill is plugged in

Test point: power outlet
Expected: Power cord inserted into outlet

10 more checks with pass and fail actions, 15 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Belt stops with overcurrent error caution

Walking surface stops and error code displayed when belt held >2 seconds

Ranked causes

1. Stopping belt > 2 seconds triggers motor overcurrent protection (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Belt tracking misaligned caution

Walking belt drifts to one side during operation, visible during treadmill running at various speeds.

Ranked causes

1. Belt tracking out of adjustment (common)

First check

Observe belt tracking at 0 mph

Test point: Walking belt position
Expected: Belt centered on rollers

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Burn hazard from hot treadmill components caution

Risk of thermal burn from contact with pulleys, chain, motor, or other treadmill parts still hot after operation

Ranked causes

1. Insufficient cooldown time after treadmill operation (common)

First check

Inspect for signs of overheating

Test point: Motor, pulleys, chain, belt area
Expected: No discoloration, odor, or visible heat shimmer

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Grade potentiometer

Grade pot requires calibration to ensure accurate incline level measurement and control.

Ranked causes

1. Grade potentiometer requires routine calibration (common)

First check

Measure siderail height at front

Test point: Bottom of front siderail to floor
Expected: Height in consistent units (inches or mm)

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Primary transformer winding resistance high voltage

Measurement of transformer primary windings continuity during fuse troubleshooting

Ranked causes

1. Transformer windings open or degraded (rare)

First check

Measure primary transformer winding resistance

Test point: Primary transformer terminals
Expected: 2 ohms or less, or less
Tools: Ohmmeter

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Transformer primary winding continuity high voltage

Measurement of transformer primary winding resistance to verify circuit integrity

Ranked causes

1. Transformer primary winding damaged or connection faulty (rare)

First check

Measure primary transformer winding resistance

Test point: Primary transformer windings
Expected: 2 ohms or less, or less
Tools: Ohmmeter

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Walking belt tension caution

Set belt tension to specification using two methods: with calipers (0.4% on dial) or without calipers (50 13/64 inches ±1/64 between marks). Belt must be properly tensioned before tracking adjustment.

Ranked causes

1. Belt tension requires calibration (common)

First check

Set calipers to zero

Test point: Both belt tension calipers
Expected: Dial reading 0.0%

3 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: walking belt tracking caution

Adjust belt alignment so it runs straight without drifting to either side during operation

Ranked causes

1. Belt tracking requires adjustment after tension change or new belt installation (common)

First check

Run treadmill at minimum speed and grade

Test point: Treadmill speed and grade controls
Expected: Treadmill running at minimum speed and grade for at least one minute

3 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Check 12 volt power supply high voltage

Verify 12 volt power supply is functioning

Ranked causes

1. 12 volt power supply failure (rare)

First check

Measure 12 volt power supply output

Test point: 12V supply output
Expected: 12 volts nominal

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Check AC Drive Module power supply high voltage

Verify power supply voltage at test points on AC Drive Module

Ranked causes

1. AC Drive Module failure (rare)

First check

Check power supply voltage at test points

Test point: AC Drive Module test points
Expected: Correct voltage for module specifications

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Check control cable for damage

Inspect cable between drive board and stress monitor for physical damage

Ranked causes

1. Control cable bent or broken pins (rare)

First check

Inspect control cable for bent or broken pins

Test point: Control cable connectors
Expected: All pins straight and intact

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Check mechanical assembly for jammed parts caution

Verify no mechanical parts are stuck or blocked in gear assemblies

Ranked causes

1. Mechanical parts jammed or blocked (occasional)

First check

Inspect mechanical assembly for jammed parts

Test point: Rack gear, grade change assembly
Expected: No obstruction, free movement

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Check outlet voltage high voltage

Verify correct voltage and power rating at power outlet and breaker

Ranked causes

1. Outlet voltage incorrect or insufficient rating (occasional)

First check

Measure outlet voltage

Test point: Power outlet
Expected: Correct rating for treadmill

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Fuse F1 or F2 blown high voltage

Treadmill fuse has failed, preventing operation

Ranked causes

1. Transformer overload or short circuit (unknown)

First check

Measure transformer primary winding continuity

Test point: Transformer primary windings
Expected: 2 ohms or less, <= 2 ohms
Tools: Ohmmeter

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

High voltage exposure risk during hood removal high voltage

Technician at risk of electrical shock from residual high voltage beneath treadmill hood after power disconnection

Ranked causes

1. Hood removal without proper power isolation and cooldown (common)

First check

Verify circuit breaker is off

Test point: Treadmill circuit breaker
Expected: OFF position

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Outlet voltage verification high voltage

Check outlet and breaker voltage matches treadmill rating requirement

Ranked causes

1. Incorrect outlet voltage rating (occasional)

First check

Measure voltage at outlet and circuit breaker

Test point: Building outlet, building circuit breaker
Expected: Correct rating for treadmill

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power to stress monitor not on

Stress monitor display or indicators show no power; unit not responding to input commands

Ranked causes

1. Stress monitor power supply off (common)

First check

Verify stress monitor power switch is on

Test point: Stress monitor power switch
Expected: Switch in On position

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Primary transformer continuity check high voltage

Check continuity of primary transformer windings during troubleshooting of blown fuses F1 or F2

Ranked causes

1. Transformer winding failure or primary fuses blown (unknown)

First check

Measure continuity of primary transformer windings

Test point: Primary transformer windings
Expected: 2 ohms or less, <= 2 ohms
Tools: Multimeter or ohmmeter

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Rear roller gap excessive caution

Gap between rear roller and guard is too large, exceeding safe operational clearance.

Ranked causes

1. Rear roller guard misaligned or worn (common)

First check

Measure gap between rear roller and guard

Test point: Rear roller guard position
Expected: Gap approximately 3/16 inch (4.8 mm), +/- 1/16 inch

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Squealing noise from drive belt

Sound similar to loose automobile fan belt during operation

Ranked causes

1. Drive belt loose (common)

First check

Listen for squealing noise characteristic of loose fan belt

Test point: Drive belt
Expected: No squealing during operation

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Squealing noise similar to automobile fan belt caution

High-pitched squealing sound from drive system during use

Ranked causes

1. Drive motor belt (poly-V drive belt) slipping (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Thumping or knocking noise correlates with belt speed caution

Rhythmic thumping or knocking that increases/decreases with walking belt speed

Ranked causes

1. Front or rear roller (pulley) assembly bearing wear (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Transformer primary winding continuity check high voltage

Diagnostic measurement to verify primary transformer integrity when fuses F1 or F2 are blown

Ranked causes

1. Primary transformer winding open or degraded (unknown)

First check

Measure primary transformer winding continuity

Test point: Primary transformer windings
Expected: 2 ohms or less, or less
Tools: Multimeter (ohms function)

Treadmill does not start high voltage

Treadmill fails to power on or begin operation when turned on.

Ranked causes

6. Fuse F1 or F2 blown (occasional)

First check

Verify treadmill is plugged in

Test point: Power outlet
Expected: Power cord connected

9 more checks with pass and fail actions, 15 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Walking belt not tracking straight

Belt drifts left or right during operation

Ranked causes

1. Belt alignment misaligned (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Walking belt slipping

Belt surface slips without gripping user foot

Ranked causes

1. Belt tension too low (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Walking belt worn out

Belt shows excessive wear, cracking, or deterioration

Ranked causes

1. Belt material degradation from age or use (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`E201`	Grade error condition	Grade system malfunction or signal loss	error
`E203`	Drive motor error condition	Drive motor malfunction or control signal loss	error
`E204`	Communications link error condition	Loss of communication between control boards or modules	error
`EPHI`	Bus voltage high or related condition	Bus voltage out of nominal range	error
`EPLO`	Bus voltage low or related condition	Bus voltage out of nominal range	error

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.