RGB LCD Shield - characters w/o backlight

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liquidlogic
 
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Joined: Wed Jan 01, 2014 5:23 pm

RGB LCD Shield - characters w/o backlight

Post by liquidlogic »

Hi,

I am having a bit of trouble with the adafruit RGB LCD shield using a RGB negative LCD. I'm able to see characters on the lcd with the contrast screwed all the way up, but there is no RGB backlight showing. Its a black display with grey characters.

All the buttons Up/Down/Left/Right/Select/Reset work, with a 73 ms 'ping' (eg Took 73 ms).

I doublechecked the solder joints, and they look ok to me. I'll upload an image for you to check.

PS - Ive used this LCD before I got the shield and it has worked fine in the past (all backlight colors worked ok). Thanks in advance for your help!
PSS - I realized this LCD isnt from adafruit, so I attached the pin assignment from the data sheet for the LCD, just in case.
Solder joints doublechecked and a few rewetted
Solder joints doublechecked and a few rewetted
rgblcdshield1.JPG (553.25 KiB) Viewed 162 times
front
front
rgblcdshield2.JPG (116.4 KiB) Viewed 159 times
lcd pin assignment
lcd pin assignment
rgblcdpins.JPG (54.8 KiB) Viewed 159 times

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adafruit_support_bill
 
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Re: RGB LCD Shield - characters w/o backlight

Post by adafruit_support_bill »

I don't see any problems with the soldering, but just for completeness, can you post another shot showing the soldering on the top-side display header?

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liquidlogic
 
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Re: RGB LCD Shield - characters w/o backlight

Post by liquidlogic »

I think I found the problem:

The comparable RGB negative LCD from adafruit has pin 15 as LED+, whereas my RGB LCD has pin 15 as LED- .
Here is reference from Adafruit (compare to my pin ref above):
http://www.adafruit.com/datasheets/rgblcddimensions.gif

So is there any way to get around this? either via editing the sketch or otherwise?
My last resort would be to desolder the lcd and replace with an adafruit model that works with this shield.

Thanks again for your help!

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adafruit_support_bill
 
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Re: RGB LCD Shield - characters w/o backlight

Post by adafruit_support_bill »

Converting from common anode to common cathode would be pretty messy. Unless you were content with a monochrome (R, G or B) backlight.

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