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  1. #21
    Hi Kev

    the photo of the breakout board is not close enough to read the lables for the connectors

    is this correct ?
    Click image for larger version. 

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    also does this 24V DC LED indicator light ???
    Click image for larger version. 

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    John
    Last edited by john swift; 23-03-2017 at 10:48 PM.

  2. #22
    Hi John sorry for the delay in replying iv'e just got in from work. The top photo of the bob you've labeled is correct, and the led is lit when powered up
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  3. #23
    Hi Kev

    going by the LED indicators the board has the DC supply OK
    and the onboard 5V regulator is working
    so I would of expected the board to work

    with out a board to test my self I'll have to do another web search to see if I can find any more information

    John

  4. #24
    Thanks John I appreciate you doing all this,
    Kev

  5. #25
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 2 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    Quote Originally Posted by john swift View Post
    looking at the breakout boards inputs

    Attachment 21208

    when the limit switch is closed, the EL817 opto isolator's NPN transistor will ground the printer ports input pin
    Going back to this photo, my calcs based on the 1k resistor, means the opto should have 24V on the pin you've marked as 5V. At 5V, the 1k resistor would limit the current to roughly 3mA, whereas 24V would give roughly 22mA. Having had a look at the datasheet for the opto, it's expecting 20mA with a forward voltage of 1.2V.

    Kev, have you measured the voltage at the top left pins on the optos?
    Try using the bottom pin on the connector for gnd, and also the main power in gnd for the voltage measurements, just in case it's a gnd fault, not a positive supply fault.

    If there is no voltage showing, is there power at the fan connector/is the fan working?
    Would it be possible to get a photo of the underside of the board, so we can see where the power supply feed to the opto comes from?
    Given the layout, I'd think the optos would take a feed from the same supply going to the fan connector, but without seeing the underside of the board, that is purely a guess.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  6. #26
    Hi John, I think I'm going to replace my bob with an upgrade. What would you recomend ?
    Kev

  7. #27
    Hi Kev

    I'm not sure what to recomend

    I was going to recomend CNC4PC's C10 breakout board
    but looking at their web site they have changed the construction

    the versions I had seen had the IC's in sockets
    making it easy to repair if something went wrong
    Click image for larger version. 

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    the latest version is like this
    Click image for larger version. 

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    this chinese BOB others have had problems with
    I have reverse engineered to find out why it didn't work as I expected
    it turns out that the 74hc14 IC used to buffer the inputs doesn't have the supply pin connected !!!!
    Click image for larger version. 

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    in a quick web search this is the closest to your BOB I have found ( may need an extra power supply)
    Click image for larger version. 

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    boards like this with opto isolated outputs are not ideal when the stepper drivers have opto isolated inputs
    Click image for larger version. 

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    breakout boards with LED indicators on the inputs could be an advantage
    at least you can see when the switch is operated

    low cost chinese board with LED input indicators
    Click image for larger version. 

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    John
    PS

    from Australia
    this MB02 from Homann Designs is a possible alternative to CNC4PC's C10

    Click image for larger version. 

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    Last edited by john swift; 26-03-2017 at 07:51 PM. Reason: add ref to MB02

  8. #28
    Hi John, I bought a bob a while ago from ebay, it looks very similar to the one in your photo, but i've never used it because someone told me it wouldn't work with my drivers, or steppers, can't quite remember which. Is that true ?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  9. #29
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 2 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    Personally, I'd try fixing the one you have first.
    It seems to be a reasonable spec, in that it uses 24V inputs, which is far better than using 5V which most BOBs do.

    It's most likely something simple, so if you can get a photo of the underside, we should be able to workout the area of the problem.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  10. #30
    Hi Kev

    thats the board with a problem with the missing positive supply to the input circuit

    Click image for larger version. 

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    what stepper drivers do you have ?

    John
    Last edited by john swift; 26-03-2017 at 09:30 PM.

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