Infant incubators · Giraffe family

GE Healthcare Giraffe Incubator: troubleshooting and error codes

The ServiceForge knowledge base holds 68 documented symptoms for the GE Healthcare Giraffe Incubator, with 142 ranked causes, 79 diagnostic checks with test points and expected values, and 70 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Unit will not power up, alarm sounds

Unit fails to power on and produces audible alarm sound

Ranked causes

1. Defective scale (unknown)
2. Defective scale harness (unknown)
3. Defective Servo Oxygen board (unknown)
4. Defective Servo Oxygen cable (unknown)
5. Defective battery (unknown)
6. Defective power supply (unknown)
7. Defective power harness to display board (unknown)
8. Defective display driver board (unknown)
9. Defective control board (unknown)

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

Elevating base will not go up or down

Bed height adjustment pedal not raising or lowering bed platform

Ranked causes

1. Pedal switches disabled in nurse or service setup screen (unknown)
2. Defective toroidal transformer (unknown)
3. No mains input to toroidal transformer (unknown)
4. Defective fuse on relay board (unknown)
5. Defective 50 pin ribbon cable between relay and control board (unknown)
6. Defective elevating base motor (unknown)
7. Defective relay board (unknown)

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

Low oxygen level patient safety

Sensor reading drops more than 3% below oxygen set point 7 minutes after a set point change

Ranked causes

1. Low O2 supply pressure or flow (common)
2. Inlet screen occluded (common)
3. Air leaks into infant compartment (occasional)
4. Supply valve not opening (occasional)
5. End cap safety valve not opening (rare)
6. Calibration valve stuck closed (occasional)
7. Infant compartment vents occluded (occasional)

First check

Verify O2 supply pressure and flow rate

Test point: O2 inlet connector
Expected: Pressure greater than 45 psi (310 kPa), flow rate greater than 45 L/min

3 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Fan not rotating detection failure

Optical sensor cannot detect fan rotation

Ranked causes

1. Fan hub not seated properly on shaft (common)
2. Defective fan motor (occasional)
3. Old design fan without grooves (occasional)
4. Defective or obstructed optical sensor (occasional)
5. Defective ribbon cable (occasional)
6. Defective relay board (rare)

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

ADD WATER message stays on even after water added

Water level indicator message does not clear after refilling reservoir

Ranked causes

1. Reservoir switch button jammed (old style units with button) (unknown)
2. Defective reservoir switch (unknown)
3. Defective 50 pin ribbon cable between relay and control board (unknown)
4. Defective relay board (unknown)
5. Defective control board (unknown)

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

Bed heater failure or no current sense high voltage

Heater commanded on but not firing or current not detected

Ranked causes

1. Bed safety thermostat open from heat shutdown (common)
2. Defective heater, thermostat, or wire harness (occasional)
3. Defective solid state relay (SSR) (occasional)
4. Defective 50-pin ribbon cable (occasional)
5. Defective relay board (rare)

First check

Allow unit to cool if recently powered off hot

Expected: Temperature drops below 40C

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

Compartment probe assembly malfunction

Compartment air probe, humidity sensor, or temperature sensor requires repair or replacement due to failure or damage.

Ranked causes

1. Humidity sensor failure or degradation (unknown)
2. Temperature sensor failure (unknown)
3. Probe housing cover damage or connector issues (unknown)
4. Disconnected or damaged electrical connectors (unknown)

First check

Inspect jack cable clip attachment

Test point: Hood back wall
Expected: Cable clip secured with 2.5 mm hex key screw

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

Oxygen probe failure patient safety

One or both sensors reading out of valid range or sensors differ by more than 3%

Ranked causes

1. Defective sensor (occasional)
2. Leak or occlusion in sensor housing area (occasional)
3. Defective cable or connection (occasional)
4. Defective Servo O2 board (rare)

First check

Verify sensor voltage readings are in valid range

Test point: sensor0, sensor1 in service mode
Expected: 23-280 millivolts for each sensor

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

Oxygen system failure 1 - sensor temperature out of range patient safety

Sensor plug thermistor temperature reading outside valid range 15°C to 55°C

Ranked causes

1. Unit temperature too cold (common)
2. Cooling fan not running when temperature exceeds 50°C (occasional)
3. Defective sensor plug thermistor or cable (occasional)
4. Defective servo O2 board (rare)

First check

Check unit ambient temperature

Test point: Room/incubator temperature
Expected: Greater than 15°C

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

Oxygen system failure 5 - persistent low oxygen after alarm silenced twice patient safety

Check O2 Supply alarm silenced twice and sensor1 reading still not greater than 23%

Ranked causes

1. O2 supply not connected (common)
2. Calibration valve stuck in calibration position (occasional)
3. Supply valves not opening (occasional)
4. Leak or occlusion in sensor housing area (occasional)

First check

Verify O2 supply connection, pressure and flow

Test point: O2 inlet
Expected: Supply connected with minimum 45 psi (310 kPa) and 45 L/min flow, >= 45 psi, >= 45 L/min

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

No AC power to unit high voltage

Unit not receiving mains AC power

Ranked causes

1. Power cord not plugged in or switch off (common)
2. Mains present but 5V supply missing (occasional)
3. Defective power supply (occasional)

First check

Verify wall power available

Expected: Live outlet with correct voltage
Tools: Voltmeter

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

No mains voltage at humidifier transformer high voltage

Isolation transformer not receiving AC power input

Ranked causes

1. Defective fuse on relay board (common)
2. Defective fuse on humidifier interface board (rev 9 or lower) (common)
3. Defective relay board (rare)

First check

Verify mains at transformer input (rev 10+)

Test point: J55 pins 1-2
Expected: Mains voltage present VAC
Tools: Voltmeter

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

Screen refreshes every few seconds while scale attached

Display screen refresh rate increases when scale is connected, causing flickering or stuttering

Ranked causes

1. Defective circuit on control board (unbiased RS485 during idle state) (unknown)
2. Defective scale (unknown)
3. Defective scale harness (unknown)

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

Unit equipped with servo-humidity but RH setpoint shows only 1-10

Humidity control setpoint display limited to values 1-10 instead of full range

Ranked causes

1. Unit powered on without compartment probe plugged in (old style units) (unknown)
2. Defective humidity sensor (unknown)
3. Defective control board (unknown)

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

Air probe sensor mismatch

Two air thermistors report temperature difference greater than 0.5C

Ranked causes

1. Defective compartment air probe (common)
2. Defective control board (rare)

First check

Measure air thermistor resistance at harness

Test point: J1 pins 1-2 and 3-4
Expected: Within 100 ohms
Tools: Ohmmeter

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

Bed down pedal pressed during startup

Bed down pedal held during power-up

Ranked causes

1. Pedal held during power-up (common)
2. Bed down pedal switch failure (occasional)

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

Bed up/down pedal switch failure

One or more bed pedal switches shorted or open

Ranked causes

1. Defective pedal switch or harness (common)
2. Defective relay board (rare)

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

Bed will not lock in tilt position patient safety

Bed platform cannot be secured when tilted, does not remain at angle

Ranked causes

1. Tilt ball not engaged in finger pocket latch (unknown)
2. Tilt brake pad failure (unknown)

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

Calibration failed - sensors not in valid range patient safety

In calibration mode, after 5 minutes both sensors not reading between 23 and 55 millivolts

Ranked causes

1. Calibration valve not opening or calibration fan not running (common)
2. Defective sensors (occasional)

First check

Verify calibration fan operation when VC opened

Test point: VC in service mode
Expected: Calibration fan running and calibration valve open

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

Elevating base does not respond to pedal controls

Pedals for raising or lowering the elevating base are non-functional during normal operation or system failure.

Ranked causes

1. System failure preventing normal pedal operation (common)
2. Pedal function disabled in service mode page 2 (occasional)

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

Elevating base motor not raising or lowering patient safety

Motor fails to respond to footswitch or control commands; base stuck in raised or lowered position.

Ranked causes

1. Loss of 24V DC motor supply voltage (common)
2. Motor control signal malfunction (incorrect J37 relay board signals) (occasional)

First check

Verify 24V DC supply for raise function

Test point: J45 pins 1-2
Expected: +24V on pin 1, Ground on pin 2, 24 to 32 V
Tools: DMM

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

Fan running at high speed continuously

Fan cannot read heat sink sensor; stays in high speed mode

Ranked causes

1. Defective heat sink sensor or harness (common)
2. Defective control board (rare)

First check

Measure heat sink sensor resistance

Test point: J3 pins 1-2
Tools: Ohmmeter

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

High oxygen level patient safety

Sensor reading exceeds set point by more than 3%

Ranked causes

1. Oxygen set point recently lowered (common)
2. Supply valve not closing (occasional)

First check

Wait for oxygen stabilization after set point change

Test point: oxygen0, oxygen1 readings
Expected: Readings stabilize at new set point within several minutes

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

Incubator heaters not functioning high voltage

Heaters fail to maintain temperature or do not heat at all. Two 115V, 225W heaters connected in parallel powered by isolation transformer.

Ranked causes

1. Open circuit in bed safety thermostat or heater element (common)
2. Open circuit in heater circuit (revision 10 or higher) (common)

First check

Measure incubator heater and bed safety thermostat resistance

Test point: Between black wire on SSR and white wire on transformer output (rev 9 or lower) or between J54 harness pin 4 and black w
Expected: 24 ohms (two 48 ohm heaters in parallel)
Tools: DMM

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

No audio alarm patient safety

Audible alarm not sounding when expected during alarm condition

Ranked causes

1. Defective speaker or harness (unknown)
2. Audio driver circuitry on control board is defective (unknown)

First check

Measure speaker resistance at relay board connector

Test point: J40 pins 5-6
Expected: about 8 ohms
Tools: Ohmmeter

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

O2 Cal Lost alarm appears patient safety

Alarm displays after unit power-on or power-fail recovery, indicating oxygen sensor calibration lost

Ranked causes

1. Oxygen sensors require calibration after power event (common)
2. Oxygen sensor fault during normal operation (rare)

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

O2 calibration lost - no O2 patient safety

Servo oxygen unit has never been calibrated; unit will not operate until initial calibration performed

Ranked causes

1. Initial calibration never performed (common)
2. Cell voltage less than 33 mV (rare)

First check

Attempt oxygen calibration

Test point: Cal O2 in service mode
Expected: Calibration routine completes successfully

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

Oxygen system failure 2 - humidity sensor out of range

Relative humidity reading out of valid range (1-99%; displays 0 in service mode when out of range)

Ranked causes

1. Defective sensor plug (occasional)
2. Defective servo O2 board (rare)

First check

Measure humidity sensor voltage

Test point: J85.2 to J85.1
Expected: 0.7 to 4.0 Volts, 0.7-4.0 V

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

Oxygen system failure 6 - communication lost with Servo O2 board

Giraffe control board cannot communicate with Servo O2 board

Ranked causes

1. Defective Servo O2 board (occasional)
2. Defective cable (occasional)

First check

Verify control board to Servo O2 board cable connection

Test point: Cable connectors between boards
Expected: Cable fully seated and secure

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

Patient probe thermistor mismatch

Baby probe thermistors show difference greater than 0.5C

Ranked causes

1. Defective patient skin probe (common)
2. Defective patient probe jack wiring (occasional)

First check

Test probe in jack 1

Expected: Difference < 0.5C

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

Power supply voltages absent or out of range high voltage

Critical supply voltages (+5V, +5VSTBY, +12V) are not present or outside acceptable range at power bus connectors.

Ranked causes

1. Power supply malfunction (common)
2. Relay board +5VSTBY generation failure (occasional)

First check

Measure +5V supply voltage

Test point: J42 pins 1-2 (orange and blue wires)
Expected: 4.75 to 5.25 V, 4.75 to 5.25
Tools: DMM

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

Switch or thermostat malfunction

Membrane or mechanical switches (display panel, reservoir, elevating base, water level) do not register presses or are stuck.

Ranked causes

1. Open membrane switch contact or loose connector (common)
2. Defective water level or reservoir thermostat (occasional)

First check

Measure alarm silence switch resistance (membrane)

Test point: Display Driver bd J21 pins 1-2
Expected: Closed (< 200 ohms when pressed), < 200
Tools: DMM

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

Toroidal transformer no AC output voltage high voltage

Transformer secondary output at J44 absent or below 15 VAC; unit loses power to downstream circuits.

Ranked causes

1. Toroidal transformer primary winding or core failure (common)
2. Loss of AC mains or relay board failure preventing primary voltage (occasional)

First check

Measure toroidal transformer secondary output voltage (winding 1)

Test point: J44 pins 1-2
Expected: About 15 V AC, ±1 V
Tools: AC voltmeter

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

Unit always powers up in service screen mode

System boots directly into service mode instead of normal operating mode

Ranked causes

1. Defective dipswitch setting on control board (unknown)
2. Override switch (>37°C) on control panel shorted (unknown)

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

Unit will not switch to Baby Control Mode

System unable to activate Baby Control mode for single-patient operation

Ranked causes

1. Patient probe plugged into Jack 2 on probe panel (unknown)
2. Baby Control disabled in Service screen (unknown)

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

50 pin ribbon cable intermittent or degraded

Communication errors or intermittent failures between control and relay boards; difficulty isolating cable as cause.

Ranked causes

1. Connector pin contamination, poor seating, or internal cable damage (occasional)

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

Air temperature alarm activated although compartment below setpoint

Temperature alarm triggered even though measured temperature is below alarm threshold

Ranked causes

1. Alarm not designed to automatically reset after condition resolved (unknown)

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

Air temperature high alarm no auto-reset

Air Temp >38C or >40C alarm remains active after temperature drops below threshold

Ranked causes

1. Alarm latch does not auto-reset (common)

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

Baby Cold or Hot alarm does not trigger at setpoint offset patient safety

Temperature alarm fails to activate when set to 0.5°C or 1.0°C offset in Air Control mode

Ranked causes

1. Manual Temp Alarm disabled in Service Screen (unknown)

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

Baby Hot or Baby Cold alarms activated in Manual Mode

Temperature alarm triggering when unit is set to Manual mode

Ranked causes

1. MANUAL TEMP alarm selected in Setup screen (unknown)

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

Baby mode disabled when button pressed

Baby mode button pressed but mode is disabled in configuration

Ranked causes

1. Baby mode disabled in service configuration (common)

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

Baby temperature alarm in air mode patient safety

Baby Hot or Baby Cold alarm activates while in Air Mode

Ranked causes

1. Manual temperature alarm enabled in configuration (common)

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

Bed up/down pedal switches disabled alarm

Pedal pressed when switches disabled in configuration

Ranked causes

1. Switches disabled in configuration (common)

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

Bed warms up slowly, may not reach set temperature

Bed temperature rises more slowly than expected or fails to reach programmed setpoint

Ranked causes

1. One bed heater cartridge defective (unknown)

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

Calibration: Line voltage high voltage

Service procedure to calibrate mains voltage measurement after relay board replacement or during maintenance

Ranked causes

1. Relay board replaced or calibration required (common)

First check

Access service menu

Test point: Override button (>37)
Expected: Service screen appears

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

Calibration: Servo Controlled Oxygen patient safety

Initial or routine calibration of the oxygen sensor system using the service mode calibration routine

Ranked causes

1. Calibration required during startup (common)

First check

Verify calibration valve operation

Test point: VC (calibration valve)
Expected: Opens calibration valve and turns on calibration fan

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

Calibration: Servo Controlled Oxygen System patient safety

System must be calibrated at least every 24 hours when servo oxygen is in use. After 24 hours, unit prompts operator to perform calibration.

Ranked causes

1. Routine calibration required (common)

First check

Calibration valve opens and calibration fan activates

Test point: Calibration valve and calibration fan
Expected: Valve open, fan running

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

Check O2 supply - valves opened but sensor low patient safety

After calibration, both supply valves opened and after ~20 seconds, sensor1 reading not greater than 23%

Ranked causes

1. O2 supply not connected (common)

First check

Verify O2 supply connection and pressure

Test point: O2 inlet
Expected: Supply connected with minimum 45 psi (310 kPa) pressure, >= 45 psi

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

Elevated oxygen level - FiO2 > 26% with Servo O2 off patient safety

Oxygen level elevated but Servo O2 system is not turned on

Ranked causes

1. Leak in Servo O2 system (common)

First check

Verify Servo O2 is off and check for oxygen source

Test point: Servo O2 control and oxygen supply
Expected: Servo O2 off and no other oxygen source in use

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

Fan running in high speed with no ALWAYS HIGH message

Fan operating at maximum speed but system display shows no indication of high speed mode

Ranked causes

1. Normal condition during 90 minutes after power up or after bed mode transition (common)

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

Ground resistance check high voltage

Verification of ground continuity between line cord ground pin and electronic enclosure

Ranked causes

1. Ground resistance exceeds safe limit (unknown)

First check

Measure ground resistance between line cord ground pin and enclosure

Test point: ground pin on line cord plug to exposed metal enclosure
Expected: Less than 0.2 ohms, <0.2 Ω
Tools: electrical safety analyzer

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

Humidifier disabled - elevating base not functioning

Elevating base does not work; safety relay 2 not energized

Ranked causes

1. Defective ribbon cable to relay board (common)

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

Humidifier disabled by motor drive failure

Humidifier cannot operate due to motor drive alarm

Ranked causes

1. Motor drive failure active (common)

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

Humidifier heater malfunction high voltage

Humidifier does not heat or overheats. Two 225W heater elements with safety thermostat rated at 104V.

Ranked causes

1. Open circuit in heater element or safety thermostat (common)

First check

Measure humidifier heater resistance (115V unit)

Test point: J53.1 to J53.3
Expected: 72 ohms (two heaters in parallel), ±5 ohms
Tools: DMM

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

Humidifier heater or thermostat defective

Humidifier heating element or safety thermostat failure

Ranked causes

1. Defective heater or thermostat (common)

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

Humidifier reservoir has hairline cracks

Humidifier water container shows visible crazing or hairline fractures

Ranked causes

1. Sterilization damage to plastic reservoir (unknown)

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

Humidifier reservoir has scaling

Mineral deposits or scaling visible on inner surfaces of humidifier reservoir

Ranked causes

1. Use of tap water instead of distilled water (unknown)

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

Humidifier safety thermostat open

Humidifier heater safety thermostat open circuit

Ranked causes

1. Thermostat opened from overheating (common)

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

Incubator heat sink sensor thermistor malfunction

Heat sink sensor temperature reading incorrect or absent; thermistor resistance out of range for operating temperature.

Ranked causes

1. Thermistor degraded or open circuit (common)

First check

Measure heat sink sensor thermistor resistance at 25°C and compare to table

Test point: Control bd J3 pins 1-2
Expected: 20000 ohms at 25°C (or per table for actual temperature)
Tools: DMM or service screen

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

Leakage current measurement high voltage

Verification of leakage current at exposed metal surfaces to ensure safety compliance

Ranked causes

1. Leakage current exceeds safe limits (unknown)

First check

Measure leakage current at exposed metal surfaces (120 VAC equipment)

Test point: exposed metal surface
Expected: Less than 300 microamperes, <300 µA
Tools: approved electrical safety analyzer

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

More symptoms

Membrane switch malfunction
Motor drive failure - elevating base malfunction
Noise from speaker on power down
Oxygen system failure 3 - checksum test failed
Oxygen system failure 4 - A/D converter self-test failed
Oxygen system failure 7 - watchdog circuit error
Scale calibration required
Temperature probe reading incorrect or absent

8 more symptoms with ranked causes and checks are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`19`	No Audio Frequency	Audio circuit fault during system test	error
`20`	Display WDOG Time Out	Display driver board not responding during watchdog timer	error
`22`	During operation, the incubator heater will not turn ON	Heater control circuit failed or relay not engaging	critical
`23`	During operation the system was unable to turn the incubator heater OFF	Heater remains on or relay stuck engaged	critical
`25`	Fan rotation is not being detected	Optical fan sensor not detecting fan rotation; occurs at power-up if fan not rotating	warning
`26`	During the power up tests, the system was unable to turn off safety relay 1	Safety relay 1 not disengaging during power-up test	critical
`27`	Defective non-volatile memory	Non-volatile memory circuit failure detected	error
`28`	During operation, the display driver board lost communication with control board	Serial communication failure between display and control boards	error
`29`	Defective signal on control board	Control board signal processing circuit failure	error
`30`	Mains voltage reading LV1 is outside of the expected range	Line voltage out of safe operating range or calibration circuit fault	warning
`33`	Defective RH Solid State Relay	RH solid state relay not functioning	error
`34`	Software revision level does not match	Control board and display board software versions incompatible	error
`35`	Wrong dipswitch set up	Control board dipswitch configuration incorrect	warning
`50`	Incorrect display driver board System Software checksum	Display driver board PROM checksum error	error
`51`	Display Defective SRAM	SRAM circuit on display driver board failed	error
`52`	Display No Timer2	Timer2 function on display driver board not available	error
`53`	Display Timer2 Too Fast	Timer2 on display driver board running at incorrect speed	error
`Air Probe Failure`	Air thermistor sensor mismatch	Temperature difference > 0.5C between two air probes	warning
`Air Temp >38C`	Compartment temperature exceeds 38 degrees C	Ambient temperature rises above 38C	warning
`Air Temp >40C`	Compartment temperature exceeds 40 degrees C	Ambient temperature rises above 40C	critical
`Baby Cold`	Baby skin temperature too low	Skin probe detects temperature below setpoint	warning
`Baby Hot`	Baby skin temperature too high	Skin probe detects temperature above setpoint	warning
`Baby Mode Disabled`	Baby mode is disabled in service configuration	Baby mode button pressed when disabled	info
`Baby Probe 1 Failure`	Patient probe 1 thermistor mismatch	Temperature difference > 0.5C in probe 1	warning
`Baby Probe 2 Failure`	Patient probe 2 thermistor mismatch	Temperature difference > 0.5C in probe 2	warning
`Bad Membrane Switch`	Front panel membrane switch panel malfunction	Switch test fails in service mode	warning
`Bed Heater Failure`	Incubator bed heater not operating or not detected	Heater commanded but current not sensed	error
`Bed Up/Down Pedal Failure`	Bed pedal switch shorted or open	Pedal switch stuck or not responding	warning
`Bed Up/Down Pedal Switches Disabled`	Pedal switches disabled by configuration	Pedal pressed when disabled in setup	info
`Calibration failed`	Calibration cannot complete; sensors not in valid range after 5 minutes	Both sensors not reading 23-55 mV during 5-minute calibration attempt	error
`Check O2 supply`	After calibration and supply valve opening, sensor not detecting oxygen	Both supply valves opened and after ~20 seconds, sensor1 <23%	warning
`Down Pedal Pressed`	Bed down pedal held during power-up	Pedal switch activated during startup	warning
`Fan Always in High Speed`	Cooling fan locked at high speed	Heat sink sensor temperature not readable	warning
`Fan Failure`	Fan rotation not detected by optical sensor	Fan not spinning or sensor malfunction	error
`FiO2>26%`	Oxygen level elevated with Servo O2 system off, indicating system leak	Sensor reading >26% oxygen when Servo O2 off and no other oxygen source in use	warning
`High Oxygen`	Oxygen level exceeds set point by more than 3%	Sensor1 reading more than 3% above set point	warning
`Humidifier Failure`	Humidifier system malfunction	Heater on but not heating or sensor fault	warning
`Low O2 alarm`	Oxygen level below acceptable threshold	During oxygen rise time test procedure	warning
`Low Oxygen`	Oxygen level below set point by more than 3%	Sensor1 reading is >3% below oxygen set point 7 minutes after set point change	warning
`Mains voltage calibration failed. Please enter the mains vol`	Dialed line voltage differs from measured value by 20% or more	Entered mains voltage value is 20% different than the measured value (not nominal value)	warning
`Motor Drive Failure`	Elevating base motor running unintended	Motor detected running when not commanded	error
`O2 Cal Lost – No O2`	Oxygen sensor calibration data has been lost or reset	Unit power-on or return from power-fail condition	warning
`O2 Cal Lost-No O2`	Servo oxygen unit never calibrated; unit will not operate until calibrated	System powered up without prior calibration	error
`Oxygen Probe Failure`	Sensor malfunction or inconsistency	One sensor reading out of range (23-280 mV) or sensors differ by >3%	error
`Oxygen System Failure 1`	Sensor temperature out of valid range 15°C to 55°C	Thermistor temperature reading outside 15-55°C range	error
`Oxygen System Failure 2`	Humidity sensor out of valid range 1-99% RH	Humidity reading out of range (displays 0 in service mode when invalid)	error
`Oxygen System Failure 3`	Microcontroller checksum test failed during power up	Checksum verification fails during system initialization	error
`Oxygen System Failure 4`	A/D converter self-test failed or Vtest out of valid range	Vtest reading outside 1.216V to 1.254V during self-test	error
`Oxygen System Failure 5`	Persistent low oxygen after Check O2 Supply alarm silenced twice	Alarm silenced twice and sensor1 still not >23%	error
`Oxygen System Failure 6`	Loss of communication between Giraffe control board and Servo O2 board	System unable to establish communication during initialization	error
`Oxygen System Failure 7`	Watchdog circuit malfunction detected during power up	Watchdog self-test fails during system initialization	error
`Power Failure`	No AC power to unit or 5V supply missing	Loss of mains AC or 5V DC supply	critical
`System Failure 0`	Communication error between display driver board and control board	Self-test during power-up	critical
`System Failure 1`	No Timer2	Self-test during power-up	critical
`System Failure 11`	ADC on control board not operating to spec (too slow)	Self-test during power-up	error
`System Failure 12`	Incorrect control board system software checksum	Self-test during power-up	critical
`System Failure 13`	Defective SRAM	Self-test during power-up	critical
`System Failure 14`	Defective WDOG	Self-test during power-up	critical
`System Failure 15`	Safety Relay 1 test failure - unable to turn incubator heater on or off	Self-test during power-up or system calibration	critical
`System Failure 16`	Incubator heater could not be turned off during power-on self test	Power-on self test	critical
`System Failure 18`	Defective Variables	Self-test during power-up	error
`System Failure 2`	Timer2 too fast	Self-test during power-up	critical
`System Failure 3`	During ADC calibration, software detected a channel out of range	During system calibration	warning
`System Failure 5`	Volt reference is out of range	Self-test during power-up	error
`System failure 55`	Display board On Line Self Test Failure	Display board self-test fails during power-up sequence	critical
`System Failure 6`	Defective overtemp DAC circuit on control board	Self-test during power-up	error
`System Failure 7`	1.0V Thermistor reference voltage is out of range	Self-test during power-up	error
`System Failure 8`	No Line Frequency	Self-test during power-up	critical
`System failure 98`	Overflow condition detected	Software overflow or buffer overrun	error
`System failure 99`	Logic problem on control board	Control board software logic error	error

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