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Support Forum » LCD displays all pixels instead of the "Congratulation" message

November 05, 2009
by tmd82983
tmd82983's Avatar

Hello all,

I just get the new kit a week ago. I followed the instruction to hook up the wires to try it out. Instead of the "congratulation ...." message, the entire LCD is filled with rectangular blocks of pixels.

Any idea of what causes this?

Thanks,

Tom

November 05, 2009
by hevans
(NerdKits Staff)

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Hi Tom,

The all black blocks can mean several things.

  1. The all black could indicate you have the wrong contrast resistor (or no contrast resistor at all). Make sure you followed step 4, of Step 4a of the guide. This has you connect the contrast resistor between GND and pin 3 of the LCD. Admittedly this is sometimes an easy step to miss. A clarification for that step in the guide is in the works.
  2. It it could mean that the LCD is getting power, but just isn't getting data it recognizes at all. Check that the connections to the LCD are nice and snug, and that the power connections to the chip are in the right place.
  3. It could be something we haven't thought of =). Send us an email at support <at> nerdkits <dot> com, with a good high res photo of your setup, maybe we can spot the problem, or help you isolate the part that is misbehaving.

Humberto

November 05, 2009
by tmd82983
tmd82983's Avatar

Humberto,

Thank you for your fast response.

I found the problem. I have the Positive battery input on C30 instead of C28.

November 06, 2009
by tech20
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This affecy happens when tooo much voltage is supplied to the lcd. just check your voltage regulator, because he no signl sign it lines 1 & 3 are solid, but 2 & 4 are blank.

November 07, 2009
by tech20
tech20's Avatar

sorry, idk why the keyboard acted that way, but what i meant to say was that this means there is a problem with your voltage, so use a multimeter to check if somethings wrong

January 06, 2010
by omer921
omer921's Avatar

i pluged in the wire from rpw 27 to pin 3 and he lcd turns off

January 06, 2010
by omer921
omer921's Avatar

i pluged in the wire from row 27 to pin 3 and the lcd turns off

January 06, 2010
by mongo
mongo's Avatar

According to the guide, row 27 is connected to one end of the 1K resistor (Brown, Black, Red) and the other end is ground. If the resistor is too large, you might get the weird display and if it's too small, other things might happen. I hate to think this but it may have been damaged by a supply voltage too high. If the battery was connected to the output terminal (30) instead of the input terminal (28), the possibility of sending 9V to the circuit comes into play. Over-voltage can cause damage to the circuitry.

Double check all of the power connections before powering up and it doesn't hurt to recheck all of the other connections too. One thing to be very aware of is that even a brief reversal of power to the LCD can cause it to fail - permanently.

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