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LCD Problem - becomes white and program stops


#1

Hello!

I have a FEZ Cobra with 3.5" LCD display (as a part of the OEM package) which I am attempting to integrate into a product development. I am facing a problem with the LCD.

My FEZ Cobra runs a program using SPI, HTTP request-response processing, SD card access and a simple UI window. A dispatch timer periodically updates the UI: What happens is that after about 20 - 30 mins of program run, the LCD turns white and the program stops. The module cannot be reached over USB (or ethernet). I noticed that the 3.3V regulator starts overheating. I have to power out the board, wait for few minutes and then on power-up the program runs fine and then after sometime (usually 20 mins or so, but It has also run longer or sometimes the problem appeared in few minutes). I have updated the firmware to 4.1.6 (30.June 2011). Has anyone faced this problem? I have tried both external power supply (6V DC), USB and regulator 5V connected to 5V in, but no luck.

Thanks for any help!

Ganesh


#2

See the image here http://www.ghielectronics.com/images/catalog/241-1_large.jpg

Look at the upper right corner at the backlight circuit. Can you please take a picture of your board and post here?


#3

Hi Gus,

Thanks for the clue! I noticed that the smd capacitor (10 uF?) had a slightly browned out on top. I replaced it with a normal electrolytic cap (10 uF, 25V) and since then it has been working fine (for the past 40 mins). Usually it was crashing (i.e LCD turning white, program stopping) after about 15- 20 mins. I will keep a watch on it to see if the issue is resolved. Did you also suspect the capacitor as a cause?

Regards

Ganesh


#4

Make sure the polarity is correct. Use volt meter to check polarity.


#5

Just to confirm - the LCD is running fine since the capacitor change. Thanks!