LCD backlight not working

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#1
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Hi Freaks,

I am using a 2x8 HD44780 LCD. The LCD is working fine and is displaying what it should. However, the backlight does not seem to be working.

The datasheet mentions forward voltage of 4.1V and a current of 60 mA. This gives me about 15ohms from a
5V supply. Here is how I am connecting it:
5V --> 15 ohms -->Anode of LCD (A).
Cathode of LCD (K) to GND.

Is there something obvious I am missing? The LCD module has a two holes marked A and K near the display.

Spec. is attached.
Thanks.

Attachment(s): 

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Looks like you are doing it correctly.

Check the wiring again, and do you have another LCD you can try, (just the back light, you don't have to hook up the entire display)?

JC

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It happens quite often that there is an flaw in the datasheet when it comes down to backlight connection. Try a 100 Ohm first with the polarity reversed (and not more than 5V !)

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tricia, and Ulyana. You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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Thanks, Jay and Nard.

I tried 15, 27 but didn't go to 100. Will try that.

Also maybe it is there, I just can't see it because of the sunlight. :) At 60 mA would it be as bright as a typical cellphone LCD?

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This might be a dumb question but what is the full part number of the display module? The datasheet states that the module is available with and without the LED backlight...

-=mike=-

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Quote:
I tried 15, 27 but didn't go to 100. Will try that.
??
Backlight connects to pin 15 and 16. IMO there are just 10 *) ways to connect it.

Nard

*) binary that is ;)

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tricia, and Ulyana. You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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Ah, you meant Ohms !
Say so next time, pls

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tricia, and Ulyana. You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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The number is AMC0802B-D-YSNRN, Mike.

Here is the website link:
[url]
http://character-lcd-lcds.shopei...
[/url]

It has the two holes on the PCB saying A and K for the backlight LED.

Sorry Plans, I meant ohms. Will be more clear in the future.:)

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From the page you linked to:

Quote:
2x8
Hot Points:
# Backlight: No
# Type: Yellow STN

Tom Pappano
Tulsa, Oklahoma

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Yep - the part number confirms its not a module with the backlight fitted.

From the website you need the AMC0802B-B-Y6WFDY part.

-=mike=-

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If happens dude, keep trying