Capnography monitors · Capnostream family

Medtronic Capnostream 35: troubleshooting and error codes

The ServiceForge knowledge base holds 14 documented symptoms for the Medtronic Capnostream 35, with 36 ranked causes, 46 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

CO2 Module not working patient safety

Capnography module fails to operate or provide measurements

Ranked causes

1. CO2 Filterline occluded or faulty (common)
2. CO2 module connectors disconnected (common)
3. CO2 tubes kinked or obstructed (occasional)
4. CO2 board failure (occasional)
5. Main Board failure (rare)

First check

Connect filterline and listen for CO2 pump sound

Test point: CO2 module pump
Expected: Audible pump sound

5 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

CO2 calibration check failed or out of specification

CO2 measurement result outside 4.7%-5.3% range during calibration check procedure

Ranked causes

1. CO2 module still warming up (occasional)
2. Incorrect or unstable calibration gas supply (common)
3. FilterLine not connected or blocked (common)
4. CO2 module internal self-test failure (rare)

First check

Verify 5% CO2 calibration gas connected

Test point: CO2 inlet connector
Expected: Gas cylinder connected with stable flow

2 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

SpO2 Module not working patient safety

Pulse oximetry module fails to operate or provide measurements

Ranked causes

1. SpO2 sensor or extension cable damaged (common)
2. SpO2 cables disconnected or loose (common)
3. SpO2 board failure (occasional)
4. Main Board failure (rare)

First check

Inspect SpO2 sensor and extension cable for physical damage

Test point: SpO2 sensor and cable
Expected: No visible damage or defects

3 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit won't turn on

Device fails to power on or boot

Ranked causes

1. Power supply failure (common)
2. Internal or removable battery depleted or faulty (common)
3. SOM Board failure (occasional)
4. Main Board failure (occasional)

First check

Verify power supply operation

Test point: Power supply connector
Expected: Power supply functional

4 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Flow rate out of specification

CO2 sample flow measurement does not meet acceptance criteria

Ranked causes

1. Mass flow meter not warmed up (occasional)
2. Blocked or restricted CO2 inlet (common)
3. Monitor pump malfunction (occasional)

First check

Allow mass flow meter to reach steady state

Test point: Mass flow meter display
Expected: Stable reading after warm-up

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

No display output

Display screen is not functioning or showing information

Ranked causes

1. Display connectors loose or disconnected (common)
2. Display module failure (occasional)
3. Main Board failure (rare)

First check

Verify display connectors are fully seated

Test point: Display connectors
Expected: All connectors properly connected

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

Micro SD card not recognized

Micro SD symbol does not appear on display after inserting Micro SD card into slot

Ranked causes

1. Micro SD slot connector loose or damaged (occasional)
2. Micro SD card incompatible or defective (common)

First check

Verify unit powered on

Test point: Unit power status
Expected: Display active and showing home screen

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

Safety leakage current exceeds limits high voltage

Electrical safety test shows earth leakage, applied part leakage, or enclosure leakage current above acceptable threshold

Ranked causes

1. Power supply unit fault or degradation (common)
2. Enclosure insulation breakdown or contamination (occasional)

First check

Measure earth leakage current

Test point: Unit under test with original power supply
Expected: ≤300 µA at mains voltage, ≤300 µA
Tools: Safety test equipment per UL60601-1

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

SpO2 readings out of tolerance patient safety

Pulse oximetry saturation or pulse values displayed do not match test source values within tolerance

Ranked causes

1. SRC-MAX sensor disconnected or faulty (common)
2. SpO2 sensor calibration drift (occasional)

First check

Verify SpO2 saturation at 75% with 200 bpm pulse

Test point: Display saturation and pulse readout
Expected: Saturation 73-77%; Pulse 197-203 bpm

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

USB flash drive not recognized

USB symbol does not appear on display after inserting USB flash drive into connector

Ranked causes

1. USB port connector loose or damaged (occasional)
2. USB flash drive incompatible or defective (common)

First check

Verify unit powered on

Test point: Unit power status
Expected: Display active and showing home screen

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

Visual inspection shows cracks or damage caution

Plastic cover or power supply unit shows visible cracks, breaks, or physical damage

Ranked causes

1. Impact damage during shipment or handling (common)
2. Power supply unit damage (occasional)

First check

Inspect plastic covers for visible damage

Test point: Front, back, and side covers of monitor
Expected: No cracks, breaks, or damage visible

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

Battery does not hold charge for minimum duration

Unit powers off before 2.5 hours on battery with FilterLine connected

Ranked causes

1. Battery degraded or defective (common)

First check

Charge battery fully

Test point: Battery charging port
Expected: Battery charged after 4 hours AC connection

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

Button functions not responding correctly

Front panel buttons do not trigger expected menu or display changes

Ranked causes

1. Button mechanical failure or contact issue (rare)

First check

Verify Menu button function

Test point: Menu button
Expected: Menu screen displayed

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

Unit does not pass leak test

Pressure loss during pneumatic seal integrity check exceeds acceptable limit

Ranked causes

1. Leak in pneumatic pathway or connectors (common)

First check

Perform leak test using digital manometer

Test point: Exhaust connector
Expected: (V1 –V2) ≤ 250 mbar, ≤250 mbar
Tools: Digital Manometer, Digital Pump, Plug

1 corrective action and part numbers 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.