Fixing a tunable-white LED ceiling lamp by replacing its insides

The driver in my Wofi LED ceiling lamp died, with no visible damage. The lamp has adjustable colour temperature and brightness – when switched on it should come back to its last settings, but it stayed completely dark.

How tunable white works

Tunable-white (CCT) lamps have two separate LED circuits – warm and cool – sharing a common positive. The colour comes from the ratio between them, and brightness from PWM on the negative side. Regulating the current itself would waste too much power.

Rating label of the GTOP GT-DR4081CW-CE driver: 200–240 V in, 22–42 V DC 810 mA out, two negative outputs and a remote antenna — The original GTOP GT-DR4081CW-CE driver: constant current (810 mA), with a common positive and two negative outputs – one per colour.

Diagnosis

There was no voltage at all on the connector to the LEDs – the fault was in the power supply itself.
The mains-side fuse (2 A, 250 V) – fine.
The other suspect near the input – also fine.
That left the switching transistor or a bigger fault.

Component side of the LED driver board, with no visible damage — The component side – no burn marks. The T2A 250V fuse by the mains terminal (bottom left) tested fine.

The lamp was probably still under warranty, but the warranty card went out with the recycling, together with the box, long ago.

The replacement

I decided the best value was to replace both the electronics and the LEDs. A controller that sets both colour temperature (warm–cool) and brightness is not easy to find, but they do exist. I used:

a 24 V 60 W power supply (EAN 5904261972012),
a CCT strip controller with an RF remote (EAN 5904261980826),
3 m of two-pin 24 V COB LED strip (EAN 5904261984244).

Everything fitted into the recess where the original driver sat. The strip went round the circular lamp two and a half times, and I had to bend it gently every 5 cm or so, so up close it looks messy. With the diffuser on you cannot tell, because a COB strip glows evenly, without dots.

Inside the lamp after the rebuild: a 24 V power supply, a mini RF LED controller and WAGO connectors — The new 24 V supply and RF controller fit where the original driver was.

Cost: about 120 PLN. From China it would have been half that, but I preferred to have the parts right away.

Two round ceiling lamps side by side: the original on the left, the repaired one on the right — The result: the original lamp (left) next to the repaired one (right).

The power supply runs on 230 V – disconnect the mains before opening the lamp.

Source: my thread on elektroda.pl (in Polish) – Naprawa/zamiennik drivera LED z regulacją barwy do lampy sufitowej (January 2026).