So, after around 3 years, one of our wardrobe lights failed. The 96 cm IKEA Norrfly LED light, with dual sensors to sense when any one of the two doors is opened.
Initially the light failed to turn on when opening the doors, this could be fixed by cycling power. After some time, even this didn't work and the only option was to manually turn the light on by setting the switch to "ON" instead of "AUTO".
After some hassle removing the light I was able to disassemble and troubleshoot the board. See attached images. Looks like the switch either grounds the low side of the LED string (ON mode), or the ground connection to the sensor electronics (AUTO mode). I probed around and found only static signals from the 8 pin controller. Also, both IR LEDs were turned off. After some pondering, I concluded that the circuit with a diode, resistor and capacitor at the controller was a reset circuit. I tried to short the capacitor using a tweezer. This revived the unit and I saw pulsing on the IR LEDs as well as corresponding sense signals from the IR sensors. My guess is that the reset circuit has a too short time constant, perhaps due to small initial margin and subsequent aging of the capacitor or controller. The original capacitance was measured to 100 nF and I added an additional 1 µF on top of it. This seems to have fixed the problem.
It would be interesting to hear if anyone had a similar problem, and any thoughts about the reset fix. Might be a Microchip microcontroller, they seem to have this kind of pinout.
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