I have a problem with my 1st project build, a clock

Discussion in 'The Projects Forum' started by John O'C, Mar 22, 2017.

  1. John O'C

    Thread Starter Member

    Mar 22, 2017
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    I have a problem with my 1st project, which I have illustrated with the photo below.

    As you can see, only one of the 7 segments is lit. (I suppose one is better than none:eek:)

    every newcomer would like the encouragement of a working project I think and I am no different.
    I would really appreciate some help to get a fully functioning clock, my fault finding skills are fairly limited at the moment, so I won't mind being treated as a simpleton, when you respond.

    Thanks upload_2017-3-22_17-42-7.png
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Schematic?

    Did you use a breadboard!

    Help us help you. Some more details, please.
     
  3. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Based on the information you have provided, what do you think a stranger 1,000 miles away can do with no test equipment, no view of the wiring, and no schematic. If you don't want to be treated as a simpleton, Think.

    In electronics anything, a schematic is everything. Even if it is perfect, seeing it rules out a ton of stuff that would take 50 postings to work through.

    Next, photos. We've all wired up stuff that wasn't pretty, so no one rational will dis you for appearance. If the wiring is overly confusing, you'll get pointers on how to clean it up.

    ak
     
  4. dl324

    AAC Fanatic!

    Mar 30, 2015
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    Welcome to AAC!
    As mentioned, we need a schematic showing how things are connected; at least how they're supposed to be.

    We also need information on the display. Is it common cathode or common anode? Is it multiplexed?

    What is the power source?
     
  5. John O'C

    Thread Starter Member

    Mar 22, 2017
    32
    4
    I built it from a kit.
    I was advised to use a kit to begin with (soldering practice et cetera). The kit is here…

    https://www.amazon.co.uk/DIY-Clock-...ital+LED+Large+Screen+Display+Clock+kit+Green

    Sorry, I don't know/understand the question

    Photo attached

    It's a USB cable
    upload_2017-3-22_18-47-58.png

    upload_2017-3-22_18-52-2.png
     
  6. John O'C

    Thread Starter Member

    Mar 22, 2017
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    Slightly better quality?
    upload_2017-3-22_19-0-3.png
     
  7. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    You have soldered the third digit the wrong way around.
    Look at the decimal point.

    Bertus
     
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  8. dl324

    AAC Fanatic!

    Mar 30, 2015
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    The link doesn't work for me.
    The displays are common anode and are being multiplexed.

    What digits are supposed to be displayed? Have you checked for any solder bridges?

    The pictures would be more useful if you posted clearly focused images of reasonable size. The component diagram might also be helpful.
     
  9. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    @dl324 , I updated the link.

    Bertus
     
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  10. John O'C

    Thread Starter Member

    Mar 22, 2017
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    bertus, it is correct, I believe. Something to do with displaying different information.
    INSTRUCTIONS: "The 3rd digit tube must be installed backwards"

     
  11. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Is the cristal (Y1) clear from the PCB?
    The metal housing could cause a short on the PCB.

    Bertus
     
  12. RichardO

    Late Member

    May 4, 2013
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    That makes sense since it was a simple way of getting a colon between the hours and minutes. I wish I had thought of doing that. :D
     
  13. John O'C

    Thread Starter Member

    Mar 22, 2017
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    4
    My apologies for the quality of the pics., but thanks for the help. I would like to resolve it though.

    It is, by about 2mm

    I have checked the soldering, no obvious solder shorting, but I am new to this.

    upload_2017-3-22_19-32-23.png
     
  14. RichardO

    Late Member

    May 4, 2013
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    It looks like there is a programming connector on the board. Did the microcontroller (U2) come programmed or did you program it? It looks like the programm is not working.
     
  15. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    It looks like the big chip is the wrong way around.
    The gap is on the right side of the drawing, but on the left on the PCB.
    I hope the chip survived.

    Bertus
     
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  16. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    To me it looks like the indent is on the left, which is consistent with the locations of the pullup resistors and the digit drivers.

    Segment B is stuck on all displays, so that's probably a clue. Pin 6 on the displays, pin 20 on the uC. The soldering looks ok but their might be a tiny crumb somewhere. All displays show it, so the multiplexed digit drive probably is ok.

    Was the uC plugged in backwards accidentally?

    ak
     
  17. John O'C

    Thread Starter Member

    Mar 22, 2017
    32
    4
    It was - How could I be so stupid?

    Thanks folks, for all your help

    You have made a 68yr old newbie very happy
     
  18. dl324

    AAC Fanatic!

    Mar 30, 2015
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    The power pins must have been arranged so backwards insertion didn't forward bias a parasitic diode and destroy the device.

    Count your lucky stars and be more careful in the future.
     
  19. John O'C

    Thread Starter Member

    Mar 22, 2017
    32
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    So….

    We have gone from 1% to 99% Success.
    Can we get to 100%?

    upload_2017-3-22_20-38-57.png

    Clue: It should read 20:28

    How can I resolve this problem?
    O.K. The middle segment is missing (left hand side)
     
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  20. John O'C

    Thread Starter Member

    Mar 22, 2017
    32
    4
    I will
     
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