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High Intensity Light - Troubleshooting Guide - NGC - TG00169

36.3 High Intensity Light - Troubleshooting Guide

Last updated: 11/12/2025

High Intensity Light - Troubleshooting Guide - NGC

TG0169

Introduction

High Intensity Lighting (HIL) are either:
  • 120VAC LED lamps . 
  • 24VDC LED lamps .

 

Symptom Table

Symptom Possible Cause Corrective Action
The light does not power on. Problem with the GFCI circuit/receptacle.

If the machine has a GFCI, check if the GFCI is tripped.
If the receptacle needs to be replaced, order the following part number:

  • For machines with 120VAC LED lamps: 74-1807
  • For machines with 24VDC LED lamps: 74-0078
Problem with the LED assembly. Check the light for damage. Check for 120 VAC or 24 VDC at the fixture connector. It must be replaced if the voltage is correct and the LED does not work. If the LED is flickering on and off, re-seat the connections. If flickering continues, replace the LED assembly.
Problem with the worklight or HIL momentary button. Go to the Diagnostics / Keyboard I/O page and toggle the button. Check the switch operation with an Ohm meter to see if the bit does not toggle in Diagnostics.
The cable from the HIL momentary button to the SKBIF is incorrectly wired. See the HIL Button Cable Incorrectly Wired section for additional details.
Incorrect input voltage selection on Worklight or HIL low voltage power supply.

Locate the 24V Work Light/HIL LVPS next to the left panel, and set the voltage input switch to 115V. 

Follow the  24V Work Light - LVPS - Replacement procedure for detailed instructions.
The light flickers. Problem with the LED assembly. Check the light for damage. Check for 120 VAC or 24 VDC at the fixture connector. If the voltage is correct and the LED does not work, it must be replaced. If the LED is flickering on and off, re-seat the connections. If flickering continues, replace the LED assembly.
Problem with the HIL/Worklight cable routing or a missing ferrite filter. This applies only to the 24VDC HIL/Worklight assemblies. Make sure the Hil/Worklight cable is routed on the left side of the cabinet. Also, make sure a ferrite filter is installed on the regen cable.
On Medium VMCs (VF-3 to VF-5), the 24V Work Table Light flickers when the machine comes on or when commanded to turn on. The machine has a 100W power supply for the work lights installed. DO NOT REPLACE THE TABLE WORK LIGHT.  Upgrade to the 200W power supply,  order 93-3521, and follow the 24V Work Light - LVPS - Replacement procedure.  

NOTE: Not all VF-3 to VF-5 with the work table option will experience light flickering. Depending on the tolerances/voltages, plugging the 3 lights into the 100W power supply in some scenarios wouldn't cause the lights to flicker as the power supply doesn't enter the overload protection mode.
Alarm 552  TRIPPED CIRCUIT BREAKER The incorrect GFCI was installed If a machine has a 120V Worklights or HIL, ensure the outlet is a GFCI. 
Note:  Machines with the 24V Worklights and HIL do not need a GFCI outlet. 

Tripped Breaker/GFI Plug

Corrective Action:

  • Check if CB2 (NGC) on the PDIST PCB has been tripped. If necessary, reset the circuit breaker.
  • Disconnect anything connected to the GFCI receptacle. Push the [RESET] button on the GFCI receptacle. Measure the voltage at the plug. When the [RESET] button is fully engaged, the voltage must measure 120 VAC.
  • If the [RESET] button does not fully engage, disconnect the light cable:
    • Work light: I/O P18-21 (NGC)
    • HIL: I/O PCB P22 (NGC)
  • Push the [RESET] button on the GFCI receptacle again.
    • The GFI plug works correctly if the [RESET] button fully engages and you have 120 VAC. Check the cable and fixtures to find the cause of the short in the light circuit.
    • If the [RESET] button does not fully engage, the GFCI receptacle is defective. Replace the GFCI receptacle.
  • After you replace the GFCI, if there is still no voltage, go to

HIL Button Cable Incorrectly Wired

Symptom: After installing HIL, pressing the momentary button on the pendant does not turn on the lights. Quickly jumping the bottom two pins on J8 on the SKBIF is 

Probable Cause: The wires going to the momentary button J8 on the SKBIF need to connect to the middle and bottom pins. The momentary signal will not trigger the HIL to turn on if it goes to the top and middle pins. 

Corrective Action: Order replacement part 33-4511. 

Electrical Diagram

115VAC HIL/Worklight LED diagram.

                            

24VDC HIL/Worklight LED diagram.