I’m looking to troubleshoot and repair which component has failed in a LED tube bulb driver. The bulb is a GE led14et8/g/4/835, and requires a ballast. These bulbs are commonly used to retrofit T8 fluorescent fixtures with LEDs.
Ideally, I’d like to either:
- Discover what SMD component has failed, and re-solder them myself.
- Bypass the embedded driver and supply 12V myself directly.
When I plug in the bulb to a fluorescent light fixture with ballast, it emits a low hum and the LEDs output a very small amount of light. Thus, they were thrown out for a reason.
Testing individual leds inside the bulbs at 12V causes them to be overloaded. Applying 3.7V causes nice bright output.
There seems to be two drivers- one at each end, with each powering 36 LEDs. I observed no obvious shorts or burn marks.
Image of what I think is the driver / power regulator, at the end of the tube:
I’ve googled the model number and different variations on the issue. I’ve also googled identifiers printed on the PCB to no avail.
Conclusion: The LEDs work. I could scratch off the coating that connects the series of LEDs, solder to that and supply my own power.
Or, I could test each component, find the faulty one and replace it. However, several of the SMD components have no label on the top, and don’t seem to have colored labeling similar to resistors.