X-ray collimators · BuckyDiagnost family

Philips NICOL Beam Limiting Device: troubleshooting and error codes

The ServiceForge knowledge base holds 31 documented symptoms for the Philips NICOL Beam Limiting Device, with 72 ranked causes, 77 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

LED LA3H1 ON, LA3H2 OFF, LA3H3 ON, LA3H4 ON or OFF patient safety

SIFLCO PCB (LA3) showing hardware defect; LA3H3 ON indicates connected hardware failure

Ranked causes

1. Shutter, iris, or filter mechanism failure (common)
2. Temperature sensor 1 failure (occasional)
3. Temperature sensor 2 failure (occasional)
4. Fan failure or connection issue (occasional)
5. Lamp failure or connection issue (occasional)

First check

Check error logging at system level

Test point: System error log
Expected: Error message identifying failed component: shutter/iris/filter, temp sensor 1, temp sensor 2, fan, or lamp

2 more checks with pass and fail actions, 6 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Light cannot be switched on via switch

Lamp does not illuminate when LAS1 switch is activated

Ranked causes

1. Connection LA3X5 loose or faulty (common)
2. Lamp voltage incorrect (common)
3. Lamp failure (occasional)
4. Micro-switch defective (occasional)
5. BLD module failure (rare)

First check

Verify LA3X5 connection

Test point: LA3X5 connector
Expected: Fully seated, no damage

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

All LEDs LA3H1 to LA3H4 are OFF caution

SIFLCO PCB (LA3) shows no indicator LEDs illuminated on power-up

Ranked causes

1. Power supply failure detected via LA2 indicators (common)
2. LA2 PCB failure (occasional)
3. LA3 PCB failure (occasional)
4. BLD unit failure (occasional)

First check

Check all LA2 power supply indicator LEDs

Test point: LA2H1, LA2H2, LA2H3, LA2H4
Expected: H1 ON (green), H2 ON (green), H3 ON (green), H4 ON (green)

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

LED LA2H1 (green +24V) is OFF caution

Power supply indicator on PSC_CAN PCB (LA2) is not illuminated, indicating 24V is not present

Ranked causes

1. System power supply failure or not operational (common)
2. Cable connection from system to LA2X2 is disconnected or faulty (common)
3. LA2 PCB failure (occasional)
4. BLD unit failure (occasional)

First check

Verify system power supply output voltage

Test point: System power output
Expected: +24V

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

LED LA2H3 (green +5V CAN) is OFF caution

5V CAN supply indicator on PSC_CAN PCB (LA2) is not illuminated

Ranked causes

1. System CAN power supply not providing 5V (common)
2. CAN cable connections LAX1 or LAX11 are disconnected or faulty (common)
3. LA2 PCB failure (occasional)
4. BLD unit failure (occasional)

First check

Verify system CAN power supply output

Test point: System CAN power output
Expected: +5V

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

LED LA2H4 (green +12V lamp) is OFF caution

12V lamp supply indicator on PSC_CAN PCB (LA2) is not illuminated

Ranked causes

1. System power supply not providing 12V lamp voltage (common)
2. Power cable LA2X2 connection is disconnected or faulty (common)
3. LA2 PCB failure (occasional)
4. BLD unit failure (occasional)

First check

Verify system power supply 12V lamp output

Test point: System 12V lamp output
Expected: +12V

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

LED LA3H1 ON, LA3H2 OFF, LA3H3 OFF, LA3H4 ON caution

SIFLCO PCB (LA3) showing no CAN communication; yellow LA3H4 ON indicates CAN issue

Ranked causes

1. CAN cable connections are disconnected or faulty (common)
2. System CAN communication failure (occasional)
3. LA2 PCB failure affecting CAN (occasional)
5. BLD unit failure (occasional)

First check

Inspect and reseat CAN connectors LA2X1 and LA2X11

Test point: LA2X1 (male), LA2X11 (female) D-connectors
Expected: Fully seated connectors, no visible damage or pin corrosion

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

LED LA2H2 (green +5V) is OFF caution

5V supply indicator on PSC_CAN PCB (LA2) is not illuminated while LA2H1 is ON

Ranked causes

1. LA3 PCB drawing excessive current or short circuit (common)
2. Internal 5V conversion failure on LA2 (occasional)
3. BLD unit failure (occasional)

First check

Measure 5V voltage at LA2MP1 test point

Test point: LA2MP1
Expected: +5V

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

Light cannot be switched on via CAN

Lamp does not illuminate when controlled through CAN interface

Ranked causes

1. CAN connection missing or faulty (common)
2. Lamp voltage incorrect (common)
3. Lamp failure (occasional)

First check

Verify CAN connection and LA3H4 status

Test point: LA3H4, CAN bus at LA2
Expected: LA3H4 is ON and CAN connected

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

Light field not completely on film

Exposed area defined by light field does not fully align with or appear on radiographic film

Ranked causes

1. Light field and X-ray field misaligned (common)
2. Light field size incorrect (common)
3. Light field shifted relative to X-ray field (occasional)

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

Replaced DSC button does not function

DSC button assembly does not operate after replacement or installation

Ranked causes

1. Incorrect DSC assembly mounted at position (common)
2. DSC-A connector not correctly mounted on LA1X16 (common)
3. DSC-B connector not correctly mounted on LA1X6 (common)

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

BLD alignment misaligned with X-ray tube patient safety

Beam limiting device axis does not coincide with X-ray tube center, causing asymmetric field or geometric errors

Ranked causes

1. Coupling flange assembly misaligned after X-ray tube or NICOL disc replacement (common)
2. Coupling flange screws loose or not fully tightened (occasional)

First check

Measure centering distances with alignment tool and film

Test point: Ring A and B projections on film at small focus and large focus
Expected: Small focus image distances P, Q and large focus image distances R, S satisfy |P|=|-R|±0.3mm and |Q|=|-S|±0.3mm

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

Collimator orientation or shutter position incorrect

BLD configured incorrectly for frontal or lateral configuration, or default shutter position and speed not set properly

Ranked causes

1. Jumper W1 on LA1 backpanel set to wrong position (occasional)
2. Software programming not set at system level (unknown)

First check

Verify LA1 jumper W1 position

Test point: Jumper W1 position on LA1 backpanel per diagram Z3-1
Expected: Jumper at 1-2 for frontal or 2-3 for lateral configuration as required

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

Electronic ruler values incorrect

Ruler position or measurement values displayed are inaccurate or wrong

Ranked causes

1. Electronic ruler failure (common)
2. LA3 SIFLCO PCB defective (occasional)

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

Fan does not operate or inadequate cooling caution

Ventilation fan fails to spin or cooling airflow is insufficient, risking equipment overheating

Ranked causes

1. Fan motor defective or bearing seized (common)
2. Fan connector disconnected or damaged (occasional)

First check

Verify fan connector is seated

Test point: Connector LA1X17
Expected: Connector fully inserted and latched

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

Filter not correctly positioned

Spectral filter is misaligned or visible in radiographic images

Ranked causes

1. LA3 SIFLCO board defective (common)
2. BLD mechanical failure (rare)

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

Lamp does not illuminate or light field misaligned radiation

Halogen lamp fails to produce light or light field does not align with X-ray field

Ranked causes

1. Halogen lamp burned out or defective (common)
2. Light field misalignment with X-ray field (occasional)

First check

Verify lamp is installed and powered

Test point: Lamp socket and power connector
Expected: Lamp seated fully in lamp-foot and connector secured

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

Micro-switch does not operate or is mispositioned patient safety

Micro-switch fails to trigger or is not positioned correctly, affecting safety or position feedback

Ranked causes

1. Micro-switch defective or worn (occasional)
2. Micro-switch bracket damaged or deformed (rare)

First check

Verify micro-switch position

Test point: Micro-switch position relative to bracket
Expected: Micro-switch positioned maximally outwards

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

No shutter movement when DSC knobs rotated

Shutter assemblies do not respond to manual rotation of DSC control knobs

Ranked causes

1. DSC assembly defective (common)
2. BLD internal linkage failure (rare)

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

Ruler does not pull out or wind up smoothly

Electronic or mechanical ruler assembly cannot be extended or retracted properly during operation

Ranked causes

1. Electronic ruler assembly worn or damaged (common)
2. Mechanical ruler assembly worn or damaged (common)

First check

Verify ruler cable connection and integrity

Test point: Connector LA5X1, cable routing through hole in LA1
Expected: Cable properly seated and routed through cable guidance with power supply and CAN cables

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

Shadow images on exposed film

Dark shadow patterns or artifacts appear on radiographic film due to shutter misalignment

Ranked causes

1. Coupling between shutters incorrect (common)
2. Coupling between main shutters and follow-shutters incorrect (occasional)

First check

Switch off power and manually close main shutters

Test point: Main shutters (item 1, Figure 8)
Expected: Fully closed

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

0° position unstable with excessive play

Swivel mechanism at 0° position exhibits excessive movement or lack of stability

Ranked causes

1. BLD mechanical wear or damage (rare)

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

Alignment of light field and X-ray field verification radiation

Procedure to verify that the X-ray field and illumination light field edges are properly aligned within tolerance limits

Ranked causes

1. Alignment drift or initial setup variation (common)

First check

Select X-ray exposure parameters

Test point: Generator controls
Expected: Large focus, 60 kV, 5 mAs selected

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

BLD does not function after DSC button replacement

BLD fails to operate after replacing DSC button or assembly

Ranked causes

1. Incorrect DSC assembly installed (common)

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

BLD does not function or start up

Beam limiting device module fails to initialize or operate

Ranked causes

1. BLD hardware failure (rare)

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

Calibration: Field Indication Plate with crossed-lines radiation

Field Indication Plate cross-lines not aligned with light field center

Ranked causes

1. Field Indication Plate misaligned on adjusting strip (common)

First check

Visually verify preconditions met

Test point: X-ray and light field alignment, output window parallel to receptor, SID
Expected: X-ray field and light field correctly aligned, output window parallel, SID 100 cm or more

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

Calibration: Lamp Adjustment After Replacing radiation

Light Field shifted in X direction after lamp replacement

Ranked causes

1. Lamp filaments incorrectly positioned after replacement (common)

First check

Check X-Ray/Light Field alignment

Test point: Field boundaries
Expected: Alignment correct per chapter 2.2.6, page 22

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

Calibration: Light Field Adjustment After Lamp Swap radiation

Light Field shifted in Y direction after lamp replacement

Ranked causes

1. Lamp pins not correctly oriented after replacement (common)

First check

Allow lamp to cool

Test point: Lamp temperature
Expected: Lamp cool enough to handle safely

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

Calibration: Light Field size adjustment radiation

Light Field size does not match X-Ray Field size

Ranked causes

1. Light Field size incorrect relative to X-Ray Field (common)

First check

Remove aesthetic covers

Test point: Aesthetic covers
Expected: Covers removed

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

LED LA3H1 ON, LA3H2 ON (blinking), LA3H3 OFF, LA3H4 ON

SIFLCO PCB (LA3) showing power-on self-test in progress; red LED blinking indicates test phase

Ranked causes

1. Normal power-on self-test operation in progress (common)

First check

Wait and observe LED state change

Test point: LA3H1, LA3H2, LA3H3, LA3H4
Expected: After ~15s: H1 ON, H2 OFF, H3 OFF, H4 OFF (normal operation) or other pattern per Table 11

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

Shutters do not close completely at start-up high voltage

Shutter assemblies remain partially open during device initialization

Ranked causes

1. Backup or near focus shutters close before main shutters (common)

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.