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PCB Troubleshooting Help - I/O Board for DDR

Discussion in 'Troubleshooting and Repair' started by Sean G, Aug 22, 2014.

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  1. Sean G

    Sean G

    8
    1
    Aug 22, 2014
    Hi Everyone.

    I'm new to these forums and relatively new to electronics (Please bear with me!)

    I have a GN845 board, which is an I/O board for a dance pad for a dance machine (DDR). The pad has 4 arrows, each controlled by the CN2, CN3, CN4, CN5 banks in the image below. CN6 is a spare and not used (Can maybe borrow component from this?)

    The up arrow is not registering at all... I traced it down to the CN2 bank of components. If I place the arrow terminals into, for example, CN3, the arrow works fine. So it sounds like there is something up with this CN2 bank.

    Does anybody have any idea on the best way to troubleshoot this kind of problem? The board is getting power because the other 3 arrows work fine. I can provide more pics of the board if needed. Thanks for the help

    [​IMG]

    [​IMG]
     
  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    Hi Sean and welcome to Electronics Point :)

    Your photos are not appearing in your post.

    If they are appearing when you view the post, perhaps that's because they're on your hard drive. In that case you need to upload them as attachments using the Upload a File button.
     
  3. OLIVE2222

    OLIVE2222

    690
    25
    Oct 2, 2011
    You can have a look at the 74HC14 output (with a multimeter) , pin 2,4,6,8,10 &12 then after the ZJS5101 filters. But if all the outputs of the arrow are out a better bet can be the (2S)D2461 transistor.
    Being "multi channel" I suggest to use a multimeter in diode test position and to compare the deffective arrow with a working one.
    see: http://www.instructables.com/id/HOW-TO-TEST-YOUR-TRANSISTORS-WITH-YOUR-MULTIMETERS/ for exemple
    being "in circuit" test result can be odd but MUST be the same as the reference arrow !
     
    Last edited: Aug 22, 2014
  4. Sean G

    Sean G

    8
    1
    Aug 22, 2014
    Thanks for the responses! :)

    KrisBlueNZ: They should be linked from my website in my original post, olive2222 must have seen them to reference some of the components in them. Are you sure they aren't working for you?

    Olive2222: Thanks for the reply, thats a great help! I'll start testing the components tomorrow and I'll get back to you.

    I did test the (2S)D2352 transistors, and they all give the same readings. I can't find the (2S)D2461 transistor you were talking about, where did you see it on the PCB?
     
  5. OLIVE2222

    OLIVE2222

    690
    25
    Oct 2, 2011
    The transistors are labeled 2SD2352 on the board but (2S)D2461 are (vertically) mounted on it, so you test it right.
     
  6. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    They're working for me now. If you haven't changed anything, I don't know why they didn't work before!
     
  7. Sean G

    Sean G

    8
    1
    Aug 22, 2014
    I've tested the component you mentioned today, they seem to give the same reading across all of the CN banks

    I tested 74HC14 pin 2,4,6,8,10 &12... I had to research how to test this, but I believe I had to use ohms with one multimeter prong on pin 7 as the ground. It gives the same reading as the other IC's.

    The ZJS5101 filters also gave the same reading.

    I did set my multimeter to ohms to measure the transistors as I do not have a diode option, would this make a difference at all?
     
  8. OLIVE2222

    OLIVE2222

    690
    25
    Oct 2, 2011
    It's OK to set the multimeter in ohms position if you lack the diode test one.
    The 74HC14 outputs as to be tested with the board powered and with the multimeter in DC position (10 volts or higher) .
    Sorry to don't mention that before. The pinout of the 74HC14 is visible here https://www.google.be/search?q=74HC14&espv=2&source=lnms&tbm=isch&sa=X&ei=mrv4U427DM2qaZLfgpgO&ved=0CAYQ_AUoAQ&biw=1344&bih=714#facrc=_&imgdii=_&imgrc=VpFBXLRz5s5EcM%3A;33TxcvIedx-qBM;http%3A%2F%2Fwww.wvshare.com%2Fimg%2Fpinout%2F74HC14_l.jpg;http%3A%2F%2Fwww.wvshare.com%2FDatasheet_html%2F74HC14-PDF.html;383;346
    look at the notch for the orientation.
    The neg probe must be connected on the pin 7 and the pos one on the output.
    You must have minimum 5volts when the corresponding led is (supposedly) ON.

    Olivier
     
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