Display "0000"

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  • November 8, 2011 at 2:48 pm #1193
    Michael
    Keymaster

    Just a follow up note for anyone following this thread: the original problem reported by boxseuss was caused by a short circuit on the board due to a large amount of solder on a pin. The problem was on the 10K resistor near the bottom left of the board. The purpose of this resistor is to provide a 5V signal (and limit the current) to pin 1 of the ATmega microcontroller. Pin 1 is the reset line which needs to be held HIGH. When it goes LOW, the microcontroller resets.

    The short circuit caused this reset line to be LOW at all times, so the microcontroller was constantly being reset and would not run.

    So if your clock displays 0000 and the colon is not lit or blinking, then the microcontroller is not running at all. Check VCC, GND and reset pins on the ATmega as a first step.

    November 13, 2011 at 8:51 pm #1206
    andyskibba
    Member

    The replacement Michael sent me works awesome!

    I’m using 2 lantern batteries (6V) each to power mine, and so far so good. The voltage regulator’s not getting warm, and it makes for a nice small little package. here’s a crummy webcam pic:

    btw yes that’s an Electrical Engineering book underneath, but I’m studying for mechanical.

    November 13, 2011 at 9:27 pm #1207
    Michael
    Keymaster

    Glad to hear it Andy. Hopefully you can send a good quality picture so I can add it to the gallery! Nothing fancy, just some good resolution.

    March 20, 2014 at 5:51 am #1896
    Rage 01
    Member

    Did we find an answer to this problem?
    I am having the same issue.

    thankx

    March 20, 2014 at 12:47 pm #1897
    Michael
    Keymaster

    If your symptoms are this:
    – display only shows 0000
    – colon is not displayed
    – no buttons function
    – display is sometimes intermittent. Touching the chips on the board can affect whether the display is on or not

    THEN, this means that the ATmega328 microcontroller is not running. Here are possible causes:
    1) The ATmega328 chip is not seated in the socket correctly or is a bit loose. Try removing and securely reinserting the chip.
    2) The reset pin (pin #1 on the ATmega328) is not being held at +5V. Check the voltage on pin 1 and ensure it is 5V. If not, then check solder connections on the 10K resistor near the pin.
    3) The 16MHz crystal is not properly connected or is defective. Check the solder connections on the crystal and the two 22pF capacitors to ensure everything is connected. These crystals are sometimes defective (up to 3% of the time), but we have established the practice of testing all crystals before we include them in kits. This crystal is easily obtained from many component suppliers, or nootropic design will gladly replace it.

    March 20, 2014 at 3:37 pm #1898
    Rage 01
    Member

    My display only shows 0000 and no colon is displayed. There is no button functions at all.
    The display is not intermittent, touching the chips does nothing to change the problem.

    I have taken the ATmega328 chip out and put it back in with no change.

    I do have the program cable and tried to reprogram but again nothing changes.

    Thankx.

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