A long time ago during a clean-up salvage, I stumbled across some GU10 LED lamps which were thrown out. I wasn’t sure exactly why, but it’s rare to come across such lamps. As I don’t have a GU10-compatible fixture, I decided that I’d just tear them apart instead. I know I could have just clipped mains wires to the back … but I couldn’t be bothered. I’ve got some more interesting lamps lying around … so lets get cracking!
The lamp itself is very generic – aluminium finned heatsink, white plastic base and a label for the wattage and power. There was no Australian regulatory compliance mark (RCM), so I suspect this might have been directly imported from China (e.g. bought off the internet).
The front features a plastic lens with hexagonal patterning to diffuse the light. It likely has three 3W LEDs to meet the 9W power rating (unless, that is exaggerated, which would not be surprising either).
Getting in was not easy – ultimately, I settled on breaking the lens which gave a clear look at the MCPCB, labelled V5_E_PCB. The LEDs seem to be of the Chinese domestic “plastic domed” type, which I’ve never been particularly fond of. This design suggests it’s probably a fairly early design of LED lamp.
The driver is impressively small and compact, being in the plastic barrel. From the label, it seems Week 7 of 2011 is probably the production date.
Some creative component positioning seems to be used to make everything squeeze in, especially that “floating” high-voltage capacitor. The underside has the controller IC, marked TXM1008. There is even a cut in the PCB, suggesting that it’s designed to be isolated. Many modern LED drivers, for cost reduction and simplicity, don’t bother with isolation on the premise that users won’t have direct contact with the LEDs and circuitry.
While the unit might have been cheap and generic, they didn’t skimp on the capacitor – it seems to be a genuine Rubycon.
Taking off the transformer, the PCB is left with mostly passives save for two transistors.
Unwinding the transformer partially reveals that it is indeed isolated with a few wraps of green mylar tape to keep the enamelled copper wire windings from contact.
The LED lamp itself was very generic in its appearance and labelling and might have been directly imported from China. It doesn’t have any particularly special qualities, although the small driver being seemingly isolated from the mains was a good surprise. It was the first GU10 lamp ever to cross my bench … so that’s something in itself.
Afterward, I tried powering the LEDs from a benchtop power supply and found the output to be quite feeble for a lamp claiming to be 9W. I suspect the Chinese “3W” LEDs were performing more like 1W LEDs at this stage and the output degradation may well be the reason why the units were disposed of. At least, they didn’t fail in the more modern “flicker” mode which is often due to bond wire detachment and the driver looked like it was also fine.