I finally was in the mood to tear down one of these filamented LED bulbs.
There is something in there!
Non-isolated, don’t touch!
Someone didn’t want to solder!
Not enough space, shrinking tube will fix it
0.47R Resistor as fuse
Capacitive dropper (high voltage)
Non-isolated driver board: capacitive dropper + bridge rectifier
The LED strips are wired in series in pairs
At first I couldn’t make out any individual LED chips, but from a previous investigation I knew that there had to be some.
Closer inspection revealed bonding wires, at least at the start / end of the strip. Sadly I didn’t manage to excavate individual LED chips.
There is a hint of a wire
I didn’t have major issues with the “power supply” with these LED bulbs. No, compared to the dreadful IKEA LED bulbs (not all of them, but many), the power supply worked, but the LEDs themselves were / are not so good.
A few failure modes:
Bad spot welding
There appear to be at least two types of these LED-strips out there.
The ones I’ve encountered are based on a piece glass + chip-LEDs + phosphorous coating. They are obviously not very fond of bending and too much mechanical stress.
As you can see in the 2nd video (by mikeselectricstuff), there are strips that appear to be based on a more flexible piece of thin metal, some bending is allowed.
Finally, a little info about the power supply