Fetal monitors · Avalon family

Philips Avalon CTS: troubleshooting and error codes

The ServiceForge knowledge base holds 51 documented symptoms for the Philips Avalon CTS, with 85 ranked causes, 86 diagnostic checks with test points and expected values, and 13 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Cordless system signal reception loss or degradation patient safety

Transducer signal not received by base station; loss of communication, weak transmission, or intermittent connection in cordless fetal monitor system

Ranked causes

1. Antenna not functioning properly or not connected (common)
2. Base station enclosed in metal rack blocking RF signals (occasional)
3. Environmental RF interference from building materials or equipment (occasional)
4. Base station and transducer frequency mismatch (occasional)
5. Multiple cordless systems in same location using same frequency (occasional)
6. Transducer battery depleted or degraded (common)

First check

Verify antenna connection to base station

Test point: Standard or remote antenna connector at base station
Expected: Antenna secure and fully seated; no loose connections

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

MECG values not displayed on maternal LCD

Expected MECG values do not appear on the maternal LCD display or recorder trace after connecting ECG transducer and applying electrodes or patient simulator.

Ranked causes

1. Defective ECG transducer (occasional)
2. Defective MECG adapter cable (occasional)
3. Base station not properly connected to fetal monitor (occasional)
4. RF-related interference (occasional)

First check

Apply ECG electrodes and observe MECG display

Test point: Maternal LCD display or recorder trace
Expected: MECG values displayed

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

System completely inoperative

Base station Power-On Light does not light in standby or when switched on; unit does not respond to power inputs

Ranked causes

1. Power cord not firmly connected to base station (common)
2. Power cable damaged or defective connections (common)
3. Power cord not connected to AC mains supply (common)
4. Blown fuses (common)

First check

Power cord reseat and inspection

Test point: Power cord connections
Expected: Firm connection to base station inlet and AC mains

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

Unable to switch from ultrasound to DECG monitoring

Transducer mode change not completing successfully

Ranked causes

1. US transducer not docked (common)
2. ECG transducer lamp not green (common)
3. DECG adapter cable M1362B not connected (common)
4. DECG monitoring not started (common)

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

Broadband RF interference causing dropouts on all telemetry channels

System exhibits quiet and noisy periods. When noise source is active, all telemetry channels degrade with increased dropouts and reduced carrier-to-noise ratio (CNR). Performance returns to normal when noise source is off.

Ranked causes

1. External RF interference source active in environment (common)
2. Offending frequencies not excluded from channel search (occasional)
3. Inadequate RF channel planning in multi-device environment (occasional)

First check

Scan available RF frequency range for interference sources

Test point: Service Support Tool RF environment scan
Expected: Identification of interfering frequencies and occupied frequency ranges
Tools: Industry standard PC with Service Support Tool software, PC interface cable M1360-61675

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

Display does not function or works abnormally

Two-digit display shows missing segments, defective lamps, or LED segments flicker or appear darker/lighter than normal

Ranked causes

1. Missing display segments or defective lamps (common)
2. MIF board malfunction (occasional)
3. Display window broken or scratched (occasional)

First check

Observe display during lamp-test phase of self-test

Test point: Two-digit display
Expected: All segments illuminate without flicker; all lamps light normally

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

Transducer not communicating with base station

Transducer warning indicator blinks; transducer out of range or inactive

Ranked causes

1. Transducer out of range (common)
2. Antenna connection fault (occasional)
3. Transducer could not register (rare)

First check

Verify transducer activation status

Test point: Transducer LED indicator
Expected: Active indicator present

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

Ultrasound signal noisy with interference

US (ultrasound) signal received from fetal monitor transducer exhibits noise or interference, degrading signal quality

Ranked causes

1. Channel interference in automatic channel search mode (common)
2. Channel spacing too small in fixed frequency mode (occasional)
3. Frequency spacing too small between transducers with fixed frequency (occasional)

First check

If using automatic channel search, dock transducer to register new frequency

Test point: Transducer docked in base station slot
Expected: Transducer registers to new clean frequency; noise reduces

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

Unable to switch from DECG to ultrasound monitoring

Transducer mode change not completing successfully

Ranked causes

1. DECG adapter cable not disconnected (common)
2. US transducer lamp not green (common)
3. Ultrasound monitoring not started (common)

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

Function button(s) not responding

One or more of the top cover function buttons fail to operate when pressed.

Ranked causes

1. Button contact issue (single button) (common)
2. MIF board failure (all buttons inoperative) (occasional)

First check

Reset the system

Test point: System reset procedure
Expected: Buttons respond after reset

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

System requires RF channel optimization for multi-device deployment

Multiple telemetry devices and/or Avalon CTS systems installed in facility competing for same frequency channels, causing potential interference and dropped connections.

Ranked causes

1. No RF frequency allocation plan established (common)
2. Insufficient available frequency channels in environment (occasional)

First check

Verify RF plan exists for facility

Test point: System configuration documentation
Expected: RF plan document showing frequency allocation by device type

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

Top cover display, LEDs, and function buttons inoperative

After opening or repairing top cover, the display, all lamps, and all function buttons fail to work.

Ranked causes

1. Ribbon cable disconnected from MIF board (common)
2. MIF board failure (occasional)

First check

Verify ribbon cable connection to MIF board

Test point: Ribbon cable connector on MIF board
Expected: Cable fully seated and secure

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

Transducer communication lost

Warning indicator blinks on base station; transducer not detected

Ranked causes

1. Transducer out of range or inactive (common)
2. Antenna connection loose or disconnected (occasional)

First check

Verify transducer is active and within range

Test point: Transducer status indicator
Expected: Transducer powers on and communicates with base station

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

Transducer communication lost or out of range

Warning symbol displayed on base station; transducer not detected or unable to communicate with base station.

Ranked causes

1. Transducer out of range or not active (common)
2. Antenna connection loose or disconnected (occasional)

First check

Verify transducer is powered on and active

Test point: Transducer power button
Expected: Transducer activated

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

Transducer out of range

Warning indicator blinks on base station indicating transducer communication loss

Ranked causes

1. Transducer out of wireless range (common)
2. Antenna connection loose or disconnected (occasional)

First check

Verify transducer is active

Test point: Transducer status indicator
Expected: Transducer powered and in communication range

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

Transducer out of range or inactive

Warning symbol blinks on base station indicating connectivity issue

Ranked causes

1. Transducer out of communication range (common)
2. Antenna connection loose or disconnected (common)

First check

Verify transducer is active and within range

Test point: Transducer position relative to base station
Expected: Transducer active and within range

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

Transducer out of range or not active patient safety

Blinking lamp on base station indicating transducer communication loss

Ranked causes

1. Transducer out of communication range (common)
2. Antenna connection loose or disconnected (occasional)

First check

Verify transducer active status and distance from base station

Test point: Transducer and base station
Expected: Transducer active and within range

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

Transducer slot blocked or occupied

Warning indicator shown on base station; unable to dock transducer in selected slot.

Ranked causes

1. Slot occupied by another active transducer (common)
2. Transducer placed in wrong slot position (occasional)

First check

Verify slot is unoccupied or release blocked slot

Test point: Slot indicator on base station
Expected: Slot empty or no active transducer shown

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

Transducer slot occupied or blocked

Warning lamp blinks; slot unavailable for new transducer activation

Ranked causes

1. Slot already has an active transducer (common)
2. Transducer belongs to different base station (occasional)

First check

Verify slot is unoccupied

Test point: Base station slot display
Expected: Slot shows as available

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

Active ECG transducer cable disconnected

ECG transducer warning indicator; cable connection missing or loose

Ranked causes

1. ECG cable disconnected or loose (common)

First check

Verify ECG cable connection

Test point: ECG transducer cable connector
Expected: Cable firmly connected to transducer port

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

Active ECG transducer cable not connected

Warning symbol displayed when using active ECG transducer; external cable connection required for ECG functionality.

Ranked causes

1. ECG cable disconnected or not installed (common)

First check

Verify ECG cable is connected to active ECG transducer

Test point: ECG transducer cable connector
Expected: Cable securely connected to ECG transducer

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

Display information suspicious or incorrect patient safety

Operator reports display data appears unreliable, incorrect, or suspicious; system provides inaccurate readings

Ranked causes

1. System needs reset after anomalous operation (common)

First check

Run power-on self test

Test point: Base station display elements and transducer LEDs
Expected: All display elements briefly displayed before normal registration process starts

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

ECG transducer cable disconnected patient safety

Warning indicator blinks for active ECG transducer with missing cable connection

Ranked causes

1. ECG cable disconnected from transducer (common)

First check

Verify ECG cable connection

Test point: ECG transducer cable connector
Expected: Cable fully seated and connected

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

ECG transducer cable not connected patient safety

Warning indicator on base station for active ECG transducer without cable

Ranked causes

1. ECG transducer cable disconnected or not attached (common)

First check

Verify ECG cable is connected

Test point: ECG transducer cable connector
Expected: Cable fully seated in transducer connector

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

Error message E9 displayed

Two active transducers transmitting FHR to the same base station trigger error E9

Ranked causes

1. Two transducers docked simultaneously on same base station (common)

First check

Verify number of transducers docked on base station

Test point: Base station slots
Expected: Only one transducer docked

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

LEDs fail to light

One or more LEDs do not illuminate when they should

Ranked causes

1. LED malfunction (unknown)

First check

Verify LED illumination after system reset

Test point: LED indicators
Expected: LEDs light when they should

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

Low RF signal strength

Signal strength of the carrier is lower than expected, indicated by signal loss warning on base station and dropouts on recorder traces.

Ranked causes

1. RF environment factors affecting signal transmission (common)

First check

Observe signal loss indicator warning on base station

Test point: base station display
Expected: no signal loss warning

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

RF interference at receiver frequency

Background noise level at receiver frequency is higher than expected, causing signal degradation.

Ranked causes

1. High background noise in RF environment (common)

First check

Determine if symptom occurs in specific area or location

Test point: patient location / hospital area
Expected: consistent performance across all locations

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

RF Link lamp activation during monitoring

RF Link lamp activates when ready lamp goes out during operation

Ranked causes

1. Normal RF Link establishment (common)

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

RF system signal loss or dropout patient safety

Momentary or extended loss of signal transmission in cordless monitoring system, appearing as warning indicators and trace dropouts.

Ranked causes

1. Low signal strength or interference in RF environment (common)

First check

Confirm user complaint matches observed system performance

Test point: system operation and user report
Expected: observed and reported issues align

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

Switch from DECG to ultrasound monitoring

Procedure to change monitoring modality from direct ECG to ultrasound transducer

Ranked causes

1. Operator needs to switch monitoring modality (common)

First check

Disconnect DECG adapter cable and fetal scalp electrode

Test point: ECG transducer connector
Expected: Adapter cable M1362B and electrode removed

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

Switch from DECG to US monitoring

Procedure to change monitoring mode from direct ECG to ultrasound fetal heart rate

Ranked causes

1. Mode change required (common)

First check

Disconnect DECG adapter cable and fetal scalp electrode

Test point: ECG transducer connectors
Expected: Cable and electrode disconnected

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

Switch from ultrasound to DECG monitoring

Procedure to change monitoring modality from ultrasound to direct ECG with fetal scalp electrode

Ranked causes

1. Operator needs to switch monitoring modality (common)

First check

Dock the US transducer

Test point: Base station ultrasound slot
Expected: US transducer secured in slot

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

Switch from US to DECG monitoring

Procedure to change monitoring mode from ultrasound to direct ECG via fetal scalp electrode

Ranked causes

1. Mode change required (common)

First check

Dock US transducer

Test point: US transducer base station slot
Expected: US transducer seated in slot

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

Transducer battery low patient safety

Blinking lamp indicator on base station; transducer may not function until recharged or replaced

Ranked causes

1. Transducer battery depleted (common)

First check

Observe lamp indicator status

Test point: Base station lamp
Expected: Lamp blinking

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

Transducer battery low or depleted

Transducer warning indicator blinks; device may not function without charging

Ranked causes

1. Transducer battery depleted (common)

First check

Allow transducer to charge at base station

Test point: Transducer dock connection
Expected: Battery charging for minimum 30 minutes

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

Transducer battery low or discharged

Lamp blinks on base station; transducer unable to operate

Ranked causes

1. Transducer battery depleted (common)

First check

Charge transducer for 30 minutes

Test point: Docking station
Expected: Transducer activates and functions

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

Transducer docking and cleaning after use

Transducers require cleaning and proper docking in base station after use

Ranked causes

1. Transducers require maintenance after use (common)

First check

Transducers cleaned after use

Test point: Transducer surface
Expected: Clean and ready for storage

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

Transducer in wrong slot

Warning indicator blinks; transducer physically placed in incorrect slot position

Ranked causes

1. Transducer positioned in wrong slot (common)

First check

Verify transducer slot position

Test point: Transducer slot indicator dot on base station
Expected: Transducer aligned with position dot on base station

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

Transducer in wrong slot position

Transducer cannot dock or activate due to placement in incorrect slot

Ranked causes

1. Transducer placed in incorrect slot (occasional)

First check

Verify transducer slot position

Test point: Transducer slot with dot indicator
Expected: Transducer aligned with dot

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

Transducer not ready after power on

Ready lamp does not activate after powering on the monitor

Ranked causes

1. System initializing (unknown)

First check

Monitor ready lamp status after power on

Test point: Ready lamp
Expected: Lamp illuminates green

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

Transducer not registered

Warning indicator on base station; transducer fails to register

Ranked causes

1. Transducer registration failure (rare)

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

Transducer placed in wrong slot

Warning indicator on base station; transducer in incorrect slot position

Ranked causes

1. Transducer inserted into incorrect slot (common)

First check

Verify transducer slot position matches dot indicator

Test point: Base station slot with dot marker
Expected: Transducer placed in slot marked by dot

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

Transducer placed in wrong slot position

Transducer inserted into incorrect slot; warning indicates proper slot position should be used.

Ranked causes

1. Transducer inserted in wrong slot (common)

First check

Verify transducer slot position matches dot indicator

Test point: Base station slot positions and dot marking
Expected: Transducer positioned in slot with dot indicator match

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

Transducer pre-warming and patient safety patient safety

Transducers are pre-warmed in base station; advise patient before application to avoid thermal shock

Ranked causes

1. Transducers pre-warmed in base station (common)

First check

Verify transducer has been in base station long enough to warm

Test point: Base station slot
Expected: Transducer at body temperature

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

Transducer pre-warming procedure patient safety

Transducers must be pre-warmed to body temperature before application to patient

Ranked causes

1. Transducers stored at ambient temperature (common)

First check

Confirm transducers warm to body temperature in base station

Test point: Base station transducer slots
Expected: Transducers at body temperature

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

Transducer registration failed patient safety

Transducer unable to register with base station; unresolved after troubleshooting

Ranked causes

1. Transducer registration failure (rare)

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

Transducer slot blocked

Warning indicator blinks indicating slot is occupied by another active transducer

Ranked causes

1. Slot occupied by another active transducer (common)

First check

Verify which transducer is active in slot

Test point: Transducer bed label indicator
Expected: Confirm bed label of active transducer

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

Transducer slot blocked or unavailable

Transducer cannot dock to base station; slot is occupied by another transducer

Ranked causes

1. Slot occupied by another transducer (common)

First check

Verify which transducer occupies the slot

Test point: Transducer bed label display on base station
Expected: Bed label of currently docked transducer (e.g. 38)

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

Transducer temperature not at body temperature patient safety

Transducers may not be pre-warmed to body temperature before application

Ranked causes

1. Transducer not docked in base station for warmup (common)

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

Unusual transducer LCD display or movement inside base station

Transducer LCD shows unusual display or noise heard when shaking base station gently, indicating magnet dislodgement

Ranked causes

1. One or more magnets dislodged (common)

First check

Inspect transducer LCD and shake base station gently

Test point: Transducer LCD display and internal components
Expected: Normal LCD display; no movement or noise when shaking

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

Error codes

Code	Meaning	Trigger	Severity
`E0`	Base station or transducer error (0-9 range)	Various error conditions in base station or transducer operation	unknown
`E0`	Error code E0 (see Instructions for Use)	Unknown	unknown
`E0 to E9`	Various error conditions; refer to Instructions for Use for specific code definitions and remedies.	Equipment malfunction or operational error	unknown
`E1`	Error code E1 (see Instructions for Use)	Unknown	unknown
`E2`	Error code E2 (see Instructions for Use)	Unknown	unknown
`E3`	Error code E3 (see Instructions for Use)	Unknown	unknown
`E4`	Error code E4 (see Instructions for Use)	Unknown	unknown
`E5`	Error code E5 (see Instructions for Use)	Unknown	unknown
`E6`	Error code E6 (see Instructions for Use)	Unknown	unknown
`E7`	Error code E7 (see Instructions for Use)	Unknown	unknown
`E8`	Error code E8 (see Instructions for Use)	Unknown	unknown
`E9`	Two active transducers transmitting FHR to same base station	More than one active FHR transducer connected to base station simultaneously	error
`E9`	Error code E9 (see Instructions for Use)	Unknown	unknown

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.