Powertool led/light feature resets

[Erwin Ried]

Hello, I have an electric jigsaw that has a laser/light. You can cycle the state in this sequence off, laser, led, both, off, (...) pressing a switch button but the thing is: sometimes while you are cutting it goes back to off.

So, my first hint is this can be fixed with a cap to smooth the current the little uC (?) receives?





The 2 white wires come directly from 220V, the red black 2 pairs go to the laser module and the led. I haven't removed the black silicone because it is quite hard and I may damage the circuit but these resistors probably are just for led/laser modules. The button is momentary. I am guessing an early design had another one due the button style.

[Erwin Ried]

Well.. black stuff was easy to remove 





BTW the circuit is so simple! I would love to use this instead of USB-chargers in my atmega projects 

[SeanB]

Check the little electrolytic cap to see if it has died, and if you can fit a slightly larger value in there as well. Add a VDR across the mains input, and solder a 10n chip capacitor across the pins if the push button switch ( the 2 pins that are soldered) and it should no longer change state from mains transients. just remember every part of this circuit is at mains voltage, no isolation at all, and nothing is connected to neutral other than a single wire and 2 diodes. Every output floats at mains voltage.

[Erwin Ried]

Thanks Sean, I am gonna check the cap, there is a little white thing in the other side of that cap, diode? no markings. What value you suggest? current one is 50V 22uF

I don't have any VDR, any value you recommend?

edit: my meter says the cap is spot on