Published 31 Mar 2018

Philips LED Bulb

\\ I brought a number of Philips LED (light emitting diode) bulbs to replace compact fluorescents, with the expectation of long bulb life and low power use. But one failed within a few months, little used.

Faulty Philips 10.5W LED Bulb

===== Overview ===== {{ :electronic:philips-led:p2237645.jpg?200|Bulb label}} The faulty bulb, which has a standard 240V bayonet fitting, was labeled :




          10.5W 6500K 1055lm 95mA
             220-240V 50/60Hz
           Made in China  6EV
             9290011648B1

===== Hardware description ===== {{ :electronic:philips-led:p2237626.jpg?300|Bulb with dome removed}} These bulbs have an opaque plastic surround that comes halfway down what would normally be the actual glass bulb area. So the "bulb" is actually a semi-circular translucent plastic dome on the end - it doesn't emit any light upwards. I used a hacksaw to cut through the edge of the plastic dome, all the way around - taking care to only let the blade penetrate the plastic of the dome and not risk cutting any internal structures. Internally are 13 LEDs mounted on a flat PC board labeled "Entry Bulb G6 19UP 20150924", "E347474", "LDB-08". The only other components visible are some surface mounted 0 ohm jumpers. Internally each LED appears to have 3 LED chips, presumably red, green, blue and driven with an appropriate balance to provide 'white' light of the appropriate colour 'temperature'. The board has space for 18 LEDs numbered 1 to 19, "5" appears to be missing. Led "12" appears to have been replaced with a bridge of solder, rather crudely by hand. The board appears to be connected to controller electronics in the base via a two pin edge connector, again crudely soldered by hand.\\ \\ {{:electronic:philips-led:p2237628.jpg?300|LED board}}{{:electronic:philips-led:p2237634.jpg?300|Normal LED}} ===== Fault ===== {{ :electronic:philips-led:p2237632.jpg?300|Damaged LED}} The fault appears to be a faulty LED "11". My first thought was that a soldering iron had accidently touched and melted the LED in manufacture, and that it had subsequenlty failed. But looking at the close-ups it looks like it has split right across, so maybe it ruptured from gas build-up after overheating. ===== Summary ===== I haven't finished checking this out, and will have to test the LEDs and trace the fault. I am surprised that there appear to be hand soldered elements in these 'high tech' products. ====== References and Additional Resources ====== * [[http://www.kerrywong.com/2017/08/27/teardown-of-a-philips-dimmable-led-bulb/|Tear down of a Philips Dimmable LED Bulb]], description of another Philips led bulb * [[https://skootsone.yolasite.com/led-en.php|LED lamp from Dollar Store. Tear down and schematic diagram]] If any referenced page no longer exists, try looking for its URL on http://archive.org. \\ ----

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