It has happened again!
After about 2 years of very mild usage (bathroom mirror light), an average on-time of about 5-10 minutes per day, yet another of my many IKEA LED lamps has died. This time it was a 4.3W one, not exactly high power.
Below you’ll find a couple of images, the results of a few tests I made, and probably some inevitable ranting.
After popping off the glass dome [insert screw driver & wiggle a bit] and removing 2 screws, I opened it up and expected a blown capacitor. None of that. I tested all diodes [OK] and most capacitors, especially the electrolytic ones. At least as far as capacitance goes, they were OK. Something else must have given out.
I tested the bridge rectifier, it was still very much alive. All of the ceramic capacitors I tested looked good too. No obvious tell-tale signs of a failure (cracked packages, strange liquids, obvious carbon deposits after releasing the magic smoke).
Then I directed my attention to parts that looked fine, but still might have been dead.
I measured the resistance of this inductor and came up with several MOHm, which didn’t feel right. Unfortunately I damaged it further during removing it from the board. No sure way to tell if it really was dead before.
Finally I decided to take the little transformer apart. The primary winding had a resistance of 47mOhm, quite nice. It also used double-insulated wire, 2 layers of insulation. All the other windings were just ordinary enamel-coated wire. There were at most 2-3 layers of the yellow sticky tape between the windings.
And guess what, the LEDs still work! Just like some time ago when one of the 400lm IKEA ledare bulbs died. Same story:IKEA ledare 400lm
All that remains now is a heap of junk and yet another LED + heat-sink, which I might convert to a DC lamp later.
How long was this lamp in service? About two years. How long was it on? Not a lot. This lamp was used to illuminate my bathroom mirror, so it might have been used 5 to 10 minutes per day. Taking 10 minutes, the cumulative on-time of this lamp was about 5 days, not a lot.
I think something is clearly wrong with the power-supplies of these LED bulbs. This one did not have any thermal compound in it, which should have helped with cooling a bit. The 400lm bulb didn’t have any either. I think I see a common thing here.
The 400lm bulb has a nice metal body for a heat-sink, but didn’t use any thermal compound around the power-supply to make use of it. Only the LED-board was allowed to dump excess heat into it. The LEDs survived, the power supply died after about 24 months as well.
Does IKEA do this on purpose?
I find it sad to make the power-supplies a weak point in the design of these LED bulbs. They could live much longer, the LEDs do quite well.
This video may be of interest