Shruthi 1 Display dark

Hi everyone,

I have again a shruthi Problem… the display is so dark. I can see the letters and see that I can switch things but it’s so dark that I have to look from the side to see anything…

I screwed the trimpot for ages Counterclockwise… the light turns on but very low. Then I screwed clockwise and it gets little better till it disappears again Oo

I resoldered the trimpot and the display but no result.

Any ideas?


Does the backlight appear to work? What kind of display is it and have you soldered a current limiting resistor?

Hmm what do u mean with Backlight? Sorry English isn’t my language :slight_smile:
Its the standard Display. The shruthi Kit is about 2 years old…
Current limiting result? Dont know what u mean… i could Upload pics if u want?

Sorry I meant current limiting resistor.

Your display has an LED and a coloured filter inside - that’s what gives it its color and brightness. I want to know if this part is working. When it doesn’t, the display just look grey on dark or dark on grey…

Please post pictures!

Where should the resistor be if I soldered it?
Will look for it then…

On one of these pictures u can see very weak letters on the display. Maybe that Pic answeres if the Backlight is fine.
If I screw the Pot Counterclockwise the Blocks get brighter but not much.

Looks like you have not soldered the backlight resistor, or you have soldered the wrong part. Please post a photo of the back of the board.

Sorry wasn’t at home. Here it is!

Try adding more solder around the legs of the resistor labelled R_LCD, and heating the legs with the tip of your soldering iron. There could be a cold solder join there.

Hi Turays,
i’m sorry to say but a lot of your solder joints are quite bad. You need more heat or you need to keep your iron a bit longer on the spot. The solder needs a chance to flow.
I think if you resolder the resistor that says ‘3.3 to 68’ your display might work. I’m afraid that if your filterboard also looks like this you won’t get any sound out of it.

No need for despair just re-solder all the joints marked with a red circle. And also joints on your filterboard that look like these. Hold your iron to the joint untill it melts, add a little extra solder keep you iron there for another 2 seconds take of your iron and then wait for the joint to solidify.
You should be fine!

I focused on the backlight resistor, but it could also be one of the 16 pins of the LCD display. Add more solder and reheat all of them!

Okay. Thanks for ur help and ur advice. To be honest it was the first project for me so yeah they don’t look great… i will resolder everything tomorrow… the filter Board looks way better!

Hey im back.
I took ur advice and resoldered the marked joints and voila… it works. Nice bright lcd and the trimpot works also like a Charm.

Thanks alot! U saved my weekend!