Building Shruthi-1 Kit: C21, C22, C4 polarized?

Discontinued products Shruthi
#1

Hi all,

I just finished building the filter board of the Shruthi-1 kit I received, and something a bit strange started bothering me: the 4.7uF caps C21, C22 and C4 in my kit are polarized (or at least they had a longer and a shorter lead, and a negative strip marked on the side). As I was building, I just ignored the assembly instructions that said they should be non-polarized, and I soldered them with polarity according to the markings on the PCB. Now is this ok, or were the caps in the kit I have wrong?

If I understood the schematics correctly, they are DC-filtering audio in the inputs and outputs, so they should definitely be unpolarized?

#2

The caps are unpolarized but run from the same machines as polarized, hence have 2 different length legs and the usual marking. It will work the way you soldered them.

#3

No worry about those caps.

#4

Ok, thanks! On to the digital board then, and see you in the “succesfully assembled” thread soon, I hope :slight_smile:

#5

I suspect they use the same machines to package these caps as other polarized ones.

The stripe on the body of the capacitor (indicating the -ve lead) is the indication of it being polarized or not.

#6

My caps had both the stripe and the different length leads. But anyway, finished the assembly, put everything together, it works and sounds great (except for one dead pixel in the LCD) :slight_smile:

#7

Dead pixel? Maybe it’s a bit of dust between the frame of the LCD and the screen itself? Try Pushing a bit on the metal frame too…

#8

You’re right, it’s not a dead pixel. It looks like a black dot on the backlight. It doesn’t seem to move if I try to gently shake the unit or such. Anyway, it’s not a big problem, I don’t even notice it most of the time.

#9

Try blowing in the space between the metal frame of the LCD and the display under it - it’s accessible from the side.

#10

That helped, thanks!