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10.1" TFT LCD Display backlight not functoning?
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Please be positive and constructive with your questions and comments.

10.1" TFT LCD Display backlight not functoning?

by northoverrj on Mon Nov 29, 2021 8:42 am

I have connected the display as shown in pictures, it is being powered by a 9v 0.6amps 5.4w mains power supply. the menu board when connected lights up. the large main connector is connected to the centre of the board and it is the correct way, vcc pins connected to the red wires on the connector. the backlight connector is also attached which can only be fitted the correct way and only fits into the one connector. so everything is connected as it should be with the flat connector on the screen with the pins facing up as it slides in it seats all the way in and laid flat on the desk and is connected fine. i have tried to connect multiple inputs to it: ps2 via the composite input and hdmi from pi4, PS5 and a pc, there is nothing coming onto the display.

It seems that the driver board detects that displays are being input as when hdmi is connected and composite then inserted the solid red turns to solid green. if only the composite is connected a solid green shows and when hdmi connected it changes to solid red light. when the source button is pressed it will also change the colour of the led as it should cycling through the inputs. however the is nothing visible being displayed on the screen. from what i can tell there is no backlight illuminating so that i can see what is being displayed, i cannot shine a light through as the back is all enclosed so i cannot ell if just the backlight is not working or if the whole screen in not working. when the driver board is powered with the display connected the is no ilumination at all to indicate the backlight is coming on. is it likely to be a failed backlight or the driver board failed and not outputting power or not turning the backlight on. Is there any way to test the backlight i cant imagine that the backlights fail that often unless its the driver board faulty? it states that these can be powered from 9v to 12v so i cant see that it isnt getting enough power. any solutions or is it best to use my multieter and check there is power going to the backlight? dont want to start poking it and void any warranty. thanks in advance for assistance

northoverrj
 
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Re: 10.1" TFT LCD Display backlight not functoning?

by mikeysklar on Tue Nov 30, 2021 6:32 pm

I've been using this display without issue with a 12v / 1A power supply. It has worked well with various raspberry pi's. Your 9v / .6A sound a little light. Do you have another 2.1mm power supply you can try? Also it would be a good idea to verify you are seeing 9v from your power supply by testing the barrel jack with you multimeter.

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Re: 10.1" TFT LCD Display backlight not functoning?

by northoverrj on Wed Dec 01, 2021 3:17 pm

Hello, thanks for the reply, I couldn't find any 2.1mm 12v power supplies only have 9v. so I picked up a new one.

New power cable is 12v 2A supply.
The voltage going into the power port is 12.1v showing .76amps

12.1v showing at positive supply to the lcd back-light .76amps

Display still not lighting up or showing any signs of activity.

How is the back light turned on? I assume it's the white wire should a voltage be jumped to it or is it a signal that turns it on? Unsure what else to try now as it should have plenty of power supplied.
Thanks

northoverrj
 
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Re: 10.1" TFT LCD Display backlight not functoning?

by mikeysklar on Wed Dec 01, 2021 6:06 pm

Thank you for trying a new power supply.

There is a power button in the bottom right corner. However, some of your description makes it sounds like you have a different 10.1" TFT LCD than the one I'm think of. Which product are you using?

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Re: 10.1" TFT LCD Display backlight not functoning?

by northoverrj on Wed Dec 01, 2021 6:20 pm

No problem, Here's a link to the display kit.

https://www.adafruit.com/product/1694

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Re: 10.1" TFT LCD Display backlight not functoning?

by mikeysklar on Wed Dec 01, 2021 7:23 pm

Okay, we had been talking about different 10.1" displays.

This is the one I use:
https://www.adafruit.com/product/2261

It is good though that you updated your power supply to 12v @ 2A.

The far left button on the board is for power do you get a back light when pressed?

buttons.jpeg
buttons.jpeg (235.66 KiB) Viewed 79 times

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Re: 10.1" TFT LCD Display backlight not functoning?

by northoverrj on Wed Dec 01, 2021 7:34 pm

okay haha, now were on the same item that might be easier XD

i see yes mine wil be getting mounted into a 3d printed housing so having it as the bare screen helps ensure it will be thin.

when power is connected the light next to power comes on green for a few seconds then turns red and stays like that. when a composite is plugged in it turns and stays green. when power is connected there is nothing happenning on the display no flicker of light or anything. if the power button is pressed the red light turns off, press it again and it lights up green for a few seconds then returns to red no change to the display no backlight or anything illuminating.

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Re: 10.1" TFT LCD Display backlight not functoning?

by mikeysklar on Thu Dec 02, 2021 1:31 pm

Since your power supply appears to be good and the display is not responding at all lets try a replacement. Please e-mail support@adafruit.com requesting another #1694 unit. Include a link to this thread and your order# in the e-mail.

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Please be positive and constructive with your questions and comments.