Weak led

Hi everybody,

I just finished building my first Shruthi-1 and it works correctly (Yeah !)
There is just a little issue with the last LED.
Its light is very weak compared to the other LEDs.
Any idea ?

Thanks a lot


Hi, there are a line of 8 resistors that set the LEDs brightness, they are above LEDs 3,4 and 5. Check they are all the same value, by making sure the colour markings are the same on each of the 8 resistors.

It could be a faulty led. I’ve had to replace one myself in another project.

Thanks a lot for your answers.

Dunk -> I think you are right. I broke one of those resistors and had to replace it.
So I bought a resistor having the same value at an electronic parts store, but it is not a 5% metal one (It’s a carbon resistor, beige, not blue) I guessed it should work though…
I think that this resistor may be faulty (I’m pretty sure the value is correct)


Beige is typically 5%. Blue is typically 1%. 5% shouldn’t have that dramatic effect. Are you sure you got 220ohm and not 220k?

Qp > Aw, you are right…

I will desolder it then solder a resistor with the correct value.
Many thanks to everyone for the quick and relevant answers, I’m a complete beginner :-/

The rest of the synth is correctly working, so, hopefully, I think there is no other mistake… :slight_smile:


Yeah, I’ve built a few Shruthis using 5% 220R resistors-shouldn’t affect it. Check the colour bands carefully…

Arf, it was not that…
Must be the LED or a bad solder join.
I will check when I have more time.
For the moment, I’m going to just enjoy the sound of this little beast!