Fetal monitors · Avalon family

Philips Avalon CL: troubleshooting and error codes

The ServiceForge knowledge base holds 53 documented symptoms for the Philips Avalon CL, with 85 ranked causes, 47 diagnostic checks with test points and expected values, and 51 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

CL transducer out of range patient safety

Numeric display replaced by blank space; CL transducer LED turns cyan and intermittent INOP issued

Ranked causes

1. Distance between base station and transducer exceeds operating range (common)
2. CL transducer battery depleted (common)
3. Base station improperly mounted in metal enclosure (occasional)
4. Signal obstruction by building structure (occasional)
5. Interference from other Avalon CL or CTS systems on same channel (occasional)

First check

Measure distance and verify line of sight between base station and CL transducer

Test point: Physical separation
Expected: Distance less than 100 m/300 ft with unobstructed line of sight

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

Base station LED does not light when On/Standby button pressed

On/Standby button LED does not illuminate when pressed on base station

Ranked causes

1. System needs reset (common)
2. Interface cable not firmly connected to fetal monitor (common)
3. Fetal monitor is powered off (occasional)
4. Interface cable damaged or has defective connections (occasional)

First check

Perform system reset

Test point: Base station
Expected: LED illuminates

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

CL transducer connection failure

CL transducer parameters not activated; descending tone from base station when transducer removed

Ranked causes

1. Maximum CL transducers already active (occasional)
2. Frequency band mismatch between CL transducer and base station (occasional)
3. Antenna disconnected from PCA board (rare)
4. RF interference detected (occasional)

First check

Check Tele Info window at monitor for active CL transducers

Test point: Monitor display
Expected: Fewer than 4 active CL transducers or transducer can activate

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

CL Pods cannot be charged

CL Pods fail to charge at cableless charging contacts on base station despite being placed in charging dock.

Ranked causes

1. Battery defect (common)
2. Cableless charging contacts defect (occasional)
3. Base station interface defect (occasional)

First check

Swap CL Pod with known good pod in same charging slot

Test point: CL base station charging dock
Expected: Known good pod charges normally

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

CL Pods not recognized at monitor

Monitor does not display or respond to CL Pods despite pods being present and powered at base station.

Ranked causes

1. CL Pods not assigned to base station (common)
2. CL Pods out of communication range (common)
3. CL Pods improperly charged or battery depleted (common)

First check

Verify CL Pod assignment in monitor settings

Test point: Monitor configuration menu
Expected: CL Pods listed as assigned to active base station

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

No Tele symbol displayed on fetal monitor patient safety

The Tele symbol does not appear on the fetal monitor screen when Avalon CL base station is connected

Ranked causes

1. Base station not properly connected to fetal monitor (common)
2. Fetal monitor cannot recognize base station (occasional)
3. Base station in standby mode (common)

First check

Verify interface cable connection

Test point: Connection between base station and fetal monitor
Expected: Cable firmly connected to both devices

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

Parameter measurements not possible patient safety

System fails to perform or display parameter measurements; mode not shown on recorder trace or displays

Ranked causes

1. System not connected correctly to fetal monitor (common)
2. Interface cable not properly connected (common)
3. Fetal monitor recorder switched off (common)

First check

Verify correct interface cable type

Test point: Interface cable between base station and fetal monitor
Expected: Cable matches technical specifications for this system

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

Transducer malfunction patient safety

INOP tone and numeric replaced by question mark on fetal monitor display

Ranked causes

1. Transducer not properly assigned to base station (common)
2. Transducer out of range or signal blocked (common)
3. Interference from nearby wireless device (occasional)

Broadband RF interference causing intermittent noise caution

All telemetry channels show periodic signal degradation with quiet periods alternating with noisy periods; system recovers when noise source is off.

Ranked causes

1. Broadband RF noise source active in building (occasional)
2. Electrical equipment interference from same frequency band (occasional)

First check

Run RSSI scan during noisy period

Test point: Monitor OBR menu RSSI trace
Expected: RSSI values elevated on all channels during interference event

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

Charging contacts dirty or contact spring failure caution

Transducer not assigned to base station or behaves abnormally when docked; charging and communication contacts blocked by dirt or ultrasound gel; springs do not deflect properly

Ranked causes

1. Dirt, ultrasound gel, or debris on charging contacts (common)
2. Charging contact spring mechanism worn or damaged (occasional)

First check

Visual inspection of charging contacts

Test point: Docking contacts on base station and transducer
Expected: Contacts clean and clear of visible dirt, gel, or debris

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

CL transducer cannot be charged; LED remains off when docked

CL transducer LED does not illuminate and transducer does not charge when placed in dock at base station charging slot.

Ranked causes

1. Battery malfunction in transducer (common)
2. Charging contacts defect on transducer or base station (occasional)

First check

Swap transducer to different charging slot

Test point: CL base station charging slots
Expected: LED illuminates in alternate slot

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

CL transducer hardware malfunction

One of INOPs cl US Malfunction, cl Toco Batt Malf, or cl ECG/IUP Batt Malf issued at monitor; LED behavior abnormal

Ranked causes

1. CL transducer hardware failure (occasional)
2. CL transducer firmware not updated after base station firmware update (occasional)

First check

Visually inspect CL transducer for physical damage or LED malfunction

Test point: CL transducer housing and LED
Expected: No physical damage; LED responds to power and user interaction

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

Fetal monitor does not recognize connected base station patient safety

No Tele symbol displayed on fetal monitor screen; system connection not established

Ranked causes

1. Incorrect interface cable connection or missing cable (common)
2. Fetal monitor lacking required software version for base station (occasional)

First check

Verify interface cable is connected

Test point: Interface cable connector at monitor and base station
Expected: Cable firmly seated on both ends, correct cable model for interface type

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

NBP Pod battery malfunction

INOP tone indicating battery system failure in NBP Pod

Ranked causes

1. NBP Pod not properly assigned or out of range (common)
2. Wireless interference from nearby device (occasional)

NBP Pod disconnected patient safety

INOP tone indicating lost base station connection

Ranked causes

1. Pod not assigned to base station or out of range (common)
2. Wireless signal blocked or interference (occasional)

RF interference from on-channel sources caution

Specific telemetry channel shows signal degradation or dropout due to narrow-band RF interference from another device on same frequency.

Ranked causes

1. Another telemetry unit operating on same frequency (occasional)
2. External RF source interference (radio, paging, ambulance) (occasional)

First check

Run OBR channel scan to identify occupied frequencies

Test point: Monitor OBR menu in Service Mode
Expected: Scan results show quiet and occupied channels

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

SpO2 Pod battery malfunction

INOP tone indicating SpO2 Pod battery system failure

Ranked causes

1. Pod not assigned or out of range (common)
2. Wireless signal interference (occasional)

SpO2 Pod disconnected patient safety

INOP tone indicating lost wireless connection to base station

Ranked causes

1. Pod not assigned or out of range (common)
2. Signal blocked or interference present (occasional)

System is completely inoperative

Base station and associated components are not functioning

Ranked causes

1. Hardware or communications failure (unknown)
2. RF-related problem (unknown)

First check

Reset the system

Test point: Base station
Expected: System powers on and LED illuminates

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

Weak or intermittent RF signals or signal loss

Cableless transducer signals drop out, degrade, or disappear during monitoring, causing parameter measurements to be lost or transducer unable to reach ready state.

Ranked causes

1. Low carrier signal strength below expected level (common)
2. RF interference from external sources (occasional)

First check

Observe transducer LED during walk-away test

Test point: CL transducer LED
Expected: LED off in normal mode; lights cyan and emits beep when out of range

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

Avalon CL top cover malfunction caution

Top cover of Avalon CL base station not functioning properly

Ranked causes

1. Top cover board failure (occasional)

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

Base station in standby mode patient safety

Tele symbol displays but base station not actively monitoring; transducers not yet assigned

Ranked causes

1. User has not powered on base station (common)

First check

Verify base station power state

Test point: Power indicator LED on base station
Expected: LED illuminated continuously (not blinking)

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

Base station malfunction detected

INOP tone issued; base station malfunction reported

Ranked causes

1. Base station hardware failure (occasional)

First check

Review base station diagnostic procedure

Test point: Base station
Expected: Diagnostic results indicate pass or fail

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

Base station software incompatibility

INOP tone issued; base station not supported by monitor firmware

Ranked causes

1. Outdated base station software revision (occasional)

First check

Verify base station firmware version matches monitor requirements

Test point: Base station software version
Expected: Current software revision installed

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

CL Pods not activated when picked up from base station

CL Pods fail to activate or become operational when removed from charging dock despite being charged.

Ranked causes

1. Missing or expired CL2 software license (common)

First check

Verify CL2 software license at monitor

Test point: Fetal monitor software menu
Expected: CL2 option listed and licensed

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

NBP Pod battery cycle limit reached

INOP tone indicating only 50 charge/discharge cycles remain

Ranked causes

1. Battery nearing end of service life (common)

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

NBP Pod battery empty

INOP tone indicating low battery time below 30 minutes on blood pressure transducer

Ranked causes

1. NBP Pod battery depleted (common)

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

NBP Pod battery end of life

INOP tone indicating battery no longer accepts charge

Ranked causes

1. Battery expired after maximum cycles (common)

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

NBP Pod battery incompatible

INOP tone with incompatible battery message

Ranked causes

1. Wrong battery type installed (occasional)

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

NBP Pod battery temperature high

INOP tone indicating critically high battery temperature

Ranked causes

1. NBP Pod exposed to heat source or covered (common)

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

NBP Pod not in cradle

INOP tone indicating NBP Pod removed from docking cradle

Ranked causes

1. Pod removed from cradle (common)

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

NBP Pod temperature too high patient safety

INOP tone indicating battery temperature exceeds safe limit

Ranked causes

1. Pod exposed to heat or covered during use (common)

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

No transducers or pods active on base station patient safety

Base station connected and powered but no monitoring active; all transducers or pods still docked or unassigned

Ranked causes

1. Transducers not assigned to monitoring channels (common)

First check

Verify at least one transducer docked and assigned

Test point: Base station docking slots and transducer assignment status
Expected: Minimum one CL transducer or CL Pod assigned and active

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

OBR channel configuration invalid

INOP tone with configuration error message on monitor

Ranked causes

1. Radio channel configuration missing or incorrect (occasional)

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

OBR configuration incompatibility

INOP Check OBR Config issued at monitor indicating general incompatibility or configuration mismatch

Ranked causes

1. OBR configuration incomplete or mismatched with base station type (occasional)

First check

Navigate to OBR configuration setting on fetal monitor

Test point: Monitor OBR configuration menu
Expected: OBR configuration setting accessible and correct for base station type

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

Power switch or On/Standby button malfunction after top cover service caution

After opening top cover or completing repair, On/Standby button fails to respond to user input

Ranked causes

1. Power switch connection loose after top cover service (common)

First check

Inspect power switch connector

Test point: Power switch connector on main board
Expected: Connector firmly seated on PCB pins, no loose wires

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

SpO2 Pod battery cycle limit

INOP tone indicating 50 charge cycles remain before end of life

Ranked causes

1. Battery approaching service life limit (common)

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

SpO2 Pod battery end of life

INOP tone indicating battery no longer holds charge

Ranked causes

1. Battery expired after maximum service cycles (common)

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

SpO2 Pod battery incompatible

INOP tone with incompatible battery warning

Ranked causes

1. Wrong battery type in SpO2 Pod (occasional)

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

SpO2 Pod battery low

INOP tone indicating battery below 30 minutes remaining

Ranked causes

1. SpO2 Pod battery depleted (common)

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

SpO2 Pod battery temperature critical

INOP tone indicating dangerously high battery temperature

Ranked causes

1. SpO2 Pod exposed to heat or covered (common)

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

SpO2 Pod not in cradle

INOP tone indicating SpO2 Pod not seated in charging cradle

Ranked causes

1. Pod removed from cradle (common)

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

SpO2 Pod temperature too high patient safety

INOP tone indicating battery temperature exceeds safe limit during use

Ranked causes

1. Pod exposed to heat source or covered (common)

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

SRR incompatible firmware

INOP tone indicating SRR board or firmware incompatible with base station software

Ranked causes

1. SRR firmware version mismatch (occasional)

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

SRR interference on monitor

Short range radio connection experiences interference from another device; INOP tone heard

Ranked causes

1. Wireless interference from external device (common)

First check

Verify no other wireless devices operating on same frequency

Test point: Operating environment
Expected: No SRR interference detected on alternative channel

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

SRR invalid channel

INOP tone indicating radio channel configuration error

Ranked causes

1. Radio channel or channel mask incorrectly configured (occasional)

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

SRR malfunction

INOP tone indicating Short Range Radio module failure

Ranked causes

1. SRR module hardware failure or connectivity issue (occasional)

Transducer battery empty patient safety

INOP message and tone indicating critically low battery time below 15 minutes

Ranked causes

1. Battery fully depleted (common)

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

Transducer battery low

INOP message on monitor indicating low battery remaining time on wireless transducer

Ranked causes

1. Battery charge depleted (common)

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

Transducer battery malfunction

INOP tone with message indicating battery system failure detected

Ranked causes

1. Battery charger circuit failure or incompatible battery (occasional)

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

Transducer disconnected patient safety

INOP tone indicating lost connection to base station

Ranked causes

1. Wireless connection lost or blocked (common)

Transducer out of range from base station patient safety

Transducer moved beyond communication range; artificial QRS sound replaces ultrasound signal; DECG and MECG waveforms not displayed

Ranked causes

1. Transducer distance exceeds wireless communication range (common)

First check

Verify transducer within communication range

Test point: Transducer position relative to base station
Expected: Transducer signal present (US sound heard, DECG/MECG waveforms displayed)

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

Transducer temperature critical patient safety

INOP tone with temperature warning; charging interrupted if docked

Ranked causes

1. Transducer or battery overheated (occasional)

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

Error codes

Code	Meaning	Trigger	Severity
`Check OBR Config`	OBR channel configuration invalid or missing	INOP tone and message during startup or operation	error
`cl ECG/IUP Batt Low`	ECG/IUP transducer battery low	Remaining monitoring time below 30 minutes	warning
`clECG/IUP Batt Malf`	ECG/IUP transducer battery malfunction	INOP tone and message	error
`clECG/IUP Chk Temp`	ECG/IUP transducer temperature critical	INOP tone and message	warning
`cl ECG/IUP Disconn`	ECG/IUP transducer disconnected from base station	INOP tone and message	error
`!!cl ECG/IUP Empty`	ECG/IUP transducer battery critically low with escalation	Remaining monitoring time below 15 minutes	error
`!!!clECG/IUP Empty`	ECG/IUP transducer battery critically low with high escalation	Remaining monitoring time below 15 minutes	critical
`cl ECG/IUP Empty`	ECG/IUP transducer battery critically low	Remaining monitoring time below 15 minutes	error
`cl ECG/IUP Malf`	ECG/IUP transducer malfunction	INOP tone and message	error
`cl NBP Batt Empty`	NBP Pod battery empty or critically low	Remaining battery time below 30 minutes	warning
`!!!cl NBP Batt Empty`	NBP Pod battery empty with high escalation	Remaining battery time below 30 minutes	critical
`!!cl NBP Batt Empty`	NBP Pod battery empty with escalation	Remaining battery time below 30 minutes with escalation indication	warning
`cl NBP Batt Incomp`	NBP Pod battery incompatible	INOP tone and message	error
`cl NBP Batt Low`	NBP Pod battery low	Remaining battery time below 2 hours	warning
`cl NBP Batt Malf`	NBP Pod battery malfunction	INOP tone and message	error
`cl NBP Batt Temp`	NBP Pod battery temperature critically high	INOP tone and message	warning
`cl NBP Check Batt`	NBP Pod battery nearing end of life	INOP tone when only 50 charge/discharge cycles remain	warning
`cl NBP Disconnect`	NBP Pod disconnected from base station	INOP tone and message	error
`cl NBP No Cradle`	NBP Pod not in cradle	INOP tone and message	info
`cl NBP Remove`	NBP Pod temperature too high	INOP tone when battery temperature exceeds limit	error
`cl NBP Serv Batt`	NBP Pod battery end of service life	INOP tone when battery reaches end of life	error
`!!!cl SpO₂ Batt Empty`	SpO2 Pod battery empty with high escalation	Battery critically low with high escalation	critical
`!!cl SpO₂ Batt Empty`	SpO2 Pod battery empty with escalation	Battery critically low with escalation indication	error
`cl SpO₂ Batt Incmp`	SpO2 Pod battery incompatible	INOP tone and message	error
`cl SpO₂ Batt Low`	SpO2 Pod battery low	Remaining battery time below 30 minutes or 2 hours	warning
`cl SpO₂ Batt Malf`	SpO2 Pod battery malfunction	INOP tone and message	error
`cl SpO₂ Batt Temp`	SpO2 Pod battery temperature critically high	INOP tone when temperature exceeds safe limit	warning
`cl SpO₂ Check Batt`	SpO2 Pod battery nearing end of life	INOP tone when 50 charge/discharge cycles remain	warning
`cl SpO₂ Disconnect`	SpO2 Pod disconnected from base station	INOP tone and message	error
`cl SpO₂ No Cradle`	SpO2 Pod not in cradle	INOP tone and message	info
`cl SpO₂ Remove`	SpO2 Pod temperature too high	INOP tone when battery temperature exceeds limit	error
`cl SpO₂ Serv Batt`	SpO2 Pod battery end of service life	INOP tone when battery reaches end of life	error
`!!!clToco Batt Empty`	Tocodynamometer battery critically low with high escalation	Remaining monitoring time below 15 minutes	critical
`cl Toco Batt Empty`	Tocodynamometer battery critically low	Remaining monitoring time below 15 minutes	error
`!!clToco Batt Empty`	Tocodynamometer battery critically low with escalation	Remaining monitoring time below 15 minutes	error
`cl Toco Batt Low`	Tocodynamometer battery low	Remaining monitoring time below 30 minutes	warning
`cl Toco Batt Malf`	Tocodynamometer battery malfunction	INOP tone and message	error
`cl Toco Chk Temp`	Tocodynamometer temperature critical	INOP tone and message	warning
`cl Toco Disconnect`	Tocodynamometer disconnected from base station	INOP tone and message	error
`cl Toco Malf`	Tocodynamometer malfunction	INOP tone and message	error
`cl US Batt Empty`	Transducer ultrasound battery critically low	Remaining monitoring time below 15 minutes	error
`!!cl US Batt Empty`	Transducer ultrasound battery critically low with escalation	Remaining monitoring time below 15 minutes with additional indication	error
`!!!cl US Batt Empty`	Transducer ultrasound battery critically low with high escalation	Remaining monitoring time below 15 minutes with additional indication	critical
`cl US Batt Low`	Transducer ultrasound battery low	Remaining monitoring time below 30 minutes	warning
`cl US Batt Malf`	Transducer ultrasound battery malfunction	INOP tone and message	error
`cl US Check Temp`	Transducer ultrasound temperature critical	INOP tone and message when temperature exceeds safe limit	warning
`cl US Disconnect`	Transducer ultrasound disconnected from base station	INOP tone and message	error
`cl US Malfunction`	Transducer ultrasound malfunction	INOP tone with numeric replaced by question mark on monitor	error
`SRR Incompatible`	SRR board or firmware incompatible with base station	INOP tone when incompatible SRR module detected at startup	error
`SRR Invalid Chan`	SRR invalid channel configuration	INOP tone and message	error
`SRR Malfunction`	SRR module malfunction	INOP tone and message	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.