Troubleshooting & maintenance
A symptom-first fault tree for dimming flicker — flicker at low output, glow after switch-off, flicker at full output, camera banding, unsynchronised groups and far-end flicker, each with a one-step check and a fix.
"The lights are flickering" is not one fault — it is at least six. Identify which one first, then act: most cases need one wiring change or a matched driver, not new luminaires.
Before anything else, do this one test: bypass the dimmer and feed the driver directly from mains (temporary wiring — use a qualified electrician).
This one step avoids more than half of all unnecessary parts swapping.
| Symptom | Most likely cause | One-step check | Fix |
|---|---|---|---|
| Flickers at low output, fine at full | Below minimum load, or driver not marked for that method | Bypass the dimmer; steady means a matching problem | Fit a driver marked for that method; keep load above the minimum |
| Glows or blinks after switch-off | Switch breaks neutral; induced voltage or dimmer leakage | Measure residual voltage across the luminaire | Switch the live conductor; add a relay or bypass component |
| Flickers at full output | Overload or poor cooling tripping protection; abnormal mains | Check case temperature; measure mains; halve the load | Go up a wattage class and improve ventilation |
| Invisible to the eye, banding on camera | PWM frequency too low (below roughly 1 kHz) | Point a phone camera at it and look for rolling bands | Higher-frequency PWM, or analogue CC dimming |
| Groups out of sync, random flicker | Mixed makes/models; 0-10V pair too long or picking up noise | Power one branch on its own | One driver model per circuit; screen the pair away from mains |
| Only the far end flickers or dims | Voltage drop pushing the far end into undervoltage protection | Measure the far end under full load | Thicker cable, move to 24V, or feed from more than one point |
Phase-cut dimmers chop the mains waveform and the driver has to interpret what is left. A driver without Triac-compatible design cannot hold stability at small conduction angles, so it shimmers or drops out. Phase-cut also carries a minimum load — if the circuit is too small, the dimmer cannot sustain its own holding current.
The usual cause is a switch wired in the neutral: the luminaire stays energised and stray capacitance between live and earth closes a tiny loop. LEDs glow on microamps. Moving the switch to the live conductor fixes it. Dimmer leakage is the second cause and needs a different dimmer or a bypass component across the luminaire.
Not a fault — it is beat frequency: the PWM rate and the camera shutter or scan rate are not synchronised. The eye cannot see it, but video, livestreams and cabinet photography show rolling bands. Raise the PWM frequency or switch to analogue constant-current dimming.
0-10V is an analogue voltage signal, so cable drop and interference change the dimming depth at each fitting. Once the control pair runs for tens of metres, or shares a conduit with mains, the fittings stop agreeing. One driver model per circuit is the cheapest cure.
© 2026 YFX. Figures are for selection purposes. Always follow the datasheet and local wiring regulations for final installation.