Another breadboard success = PCB failure..

Discussion in 'The Projects Forum' started by Orphne, Aug 9, 2016.

  1. Orphne

    Thread Starter New Member

    Jun 10, 2016
    6
    1
    So, I am working on a project for which I need to use treadmill motors. Currently using a circuit that I found on http://el34world.com/Misc/Cnc/images/TerrysBoard2.gif I have made this circuit on breadboards twice now, and each time it has worked. I have built thew circuit on pcb 3x now and each one fails. I am beyond frustrated. I have tried both with and without the capacitors bridging + and ground and had success with a .47uF with breadboard while nothing has worked on PCB at all. Anyone who can find my error will be legend in my mind... \

    I have attached my most recent attempt.
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    905
    Welcome to AAC.

    Are your images of your breadboard or PCB's? Some people consider perfboard a type of breadboard.

    Please provide a schematic. It is not clear what you mean by capacitor bridging.

    John
     
  3. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
    It's not unusual for a circuit to behave differently when moved from breadboard to PCB. You have to anticipate that and solve any issues when they arise the first time. Rebuilding the same problem and hoping for a different outcome is an inefficient strategy.

    We need a schematic.

    In the meanwhile, I see some soldering oddities, for instance on the back side, up in X21. The possible connection between C16 and C17 is a question mark also.

    I personally feel it's sloppy to leave unsoldered thru-holes such as in Q09.
     
  4. Orphne

    Thread Starter New Member

    Jun 10, 2016
    6
    1
    The link in my original post contains a link to the schematic, should i paste it here instead?

    I will check the connections noted by wayneh, although everything seems secure up top.
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
    Can you verify that the ICs both have power on the right pins, and whether both are working? You may need to break the link between them and manually test the 2nd one.

    Did you follow or draw a breadboard diagram, or a PCB layout diagram? Those might be helpful in diagnosing things.
     
  6. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    905
    Your schematic doesn't show the treadmill motors. By "not working" I am assuming that what you want to do with those motors isn't happening.

    Please let us know what you want those motors to do and how they are connected to that circuit.

    If that is not the case, tell us what you mean by "not working."

    John
     
  7. Orphne

    Thread Starter New Member

    Jun 10, 2016
    6
    1
    Correct John. This board replaces the control panel of a treadmill and interfaces with the mc2100 controller directly.
    You can see someones complete assembly on breadboard here:
    http://el34world.com/Misc/misc/images/Img_9565.jpg

    Really I was hoping someone could isolate a simple error or missed connection. hoping.
     
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    905
    The simple answer to your question is for you to provide a schematic. Without that, we can't even make a good guess. The drive(s) probably involve mosfets, and a very common mistake is for someone to connect N-channel mosfets wrong.

    Now, if you actually had it working, including the motors, from a breadboard, providing that schematic should not be a problem.

    John
     
  9. Orphne

    Thread Starter New Member

    Jun 10, 2016
    6
    1
    I did have it working with the breadboards.

    Here is the schematic - also linked in OP. TerrysBoard2.gif
     
  10. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    905
    I don't see the motor(s) in that schematic.

    Glad it works for you.

    John
     
  11. Orphne

    Thread Starter New Member

    Jun 10, 2016
    6
    1
    This circuit generates a PWM that is sent back to the MC-2100 motor controller which provides power to the treadmill motor. There are no changes to the stock MC2100 and so I am only focusing on this 1 board.
     
  12. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    Perfboard is more errorprone since the connections are usually on the bottom side.
    While on breadboard its directly on the top side.

    Actually I often use perfboard with the copper side up, add only some connections also on bottom side at late stage or not at all.
    The parts can be removed more easily if they dont go through hole.
     
  13. hp1729

    Well-Known Member

    Nov 23, 2015
    1,957
    219
    Did you build it all in one setting? No matter how simple it is better to test it as you go along. "Not working"? What part of the circuit is not working?
     
  14. Orphne

    Thread Starter New Member

    Jun 10, 2016
    6
    1
    Thank you to all who responded. Tonight my first board worked. Two more to build tomorrow. I got new trim pots, a solder, iron and kept everything closer to the board.

    Thanks again!
     
    wayneh likes this.
  15. thisguy1

    New Member

    Aug 18, 2016
    11
    1
    Thats happened to me half a dozen times
     
Loading...