The unit otherwise operates, but lamps, meters, or the display do not work.
Safe first checks
Confirm the dimmer or display switch is not set to off.
Check the service documentation for lamp type before ordering replacements.
Do not replace lamps with a different voltage or wattage.
If several indicators failed together, treat it as a power-supply issue rather than a simple lamp issue.
Next step
Record exactly which lamps or display sections are out.
Bench Technician Steps
This is the model of work a qualified electronics technician follows using the exact service manual and suitable test equipment. It is not a do-it-yourself instruction to work on energized equipment.
Use the exact model documentation to identify the lamp, display, meter, or supply circuit involved before ordering replacements.
Determine whether the failure is isolated to one lamp or display element, or whether multiple indicators share a supply fault.
Match voltage, current, physical fit, and heat characteristics for any replacement component.