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Support Forum » Blank LCD

December 10, 2009
by Capt
Capt's Avatar

Hi, I've desolder the pin on my LCD then attached a flat ribbon cable and at the end of the ribbon, I've used two Cat5 installation cables witch i attach to the breadboard. My problem is that the lcd just showing fully enlighted pixels at line two and foure.

Have dubbel checked my connections and tested the cabels connectivity. Using the orginal Tempsensor prodject as a test.

What could be wrong? Could the heat from soldering iron roast the lcd? Is ther any way i could test the lcd "manualy"?


December 10, 2009
by mrobbins
(NerdKits Staff)

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Hi Capt,

It's not impossible, but I'd find it unlikely that desoldering the header on the LCD would send enough heat to the LCD's controller to cook it.

The fact that rows #1 and #3 still light up indicates to me that your LCD's controller is still basically operating in some capacity, and that you properly have ground, power, and contrast connections.

Unfortunately I can't think of a way to test the LCD further at this point and have to suggest a connectivity issue. I know you said you double-checked connectivity, but did you also check for unintended solder bridges between adjacent pins? Or unintended cross-connections between adjacent pins possibly within the ribbon cable itself?

Feel free to post some photos here and maybe someone can spot something out of place.


December 10, 2009
by wayward
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I did something similar: I cut the ribbon on its far end, splayed the wires and soldered them to a 14-pin DIP header. This seemed like a straightforward enough task, but in fact is quite tricky and one needs to be rather careful. In addition to what Humberto said, do triple-check if you got all the pins correctly; I remember losing quite some time before I realized I had cross-wired ground and V+. Since you're getting the LCD to light up and the contrast is good, you should check data and control lines.

December 10, 2009
by wayward
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