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Connecting a heated bed

Discussion in 'Mods and Upgrades' started by colton81, Dec 14, 2017.

  1. colton81

    colton81 Active Member

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    Well I did just a test to see if it would try to heat up and it doesn’t budge it’s like it’s not outputting any voltage. I wonder if the firmware on github has different pin layout then what robo is using


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  2. colton81

    colton81 Active Member

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    Something else I noticed. I’m not using the standard power in plug. I’m using the power in pins from my psu and next to it says bed power in. I’m curious if because I’m using the pins for the power I have to plug power in for the bed as well[​IMG]


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  3. Kilrah

    Kilrah Well-Known Member

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    Most likely yes. The stock connector has 4 pins, haven't checked but my guess is 2 are in parallel to the "bed power" header and the other 2 to the main supply you've fed to, both being separate (unless the PSU makes them common like the R2's PSU does).

    If you do "just a test to see if it would try to heat up" you're going to have to replace the 15A fuse you'll have blown in the process.
     
  4. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    @colton81 I'm at a loss, I don't exactly know how those pins are used. I do know that on a standard setup the place you plugged in those wires already has 24V output because those are the pins / socket I am using to power the extension of @Kilrah's LED mod. I am not sure what would happen if you use that to attach another power supply.

    I am pretty sure they are used if there is nothing connected to the rear power jack.

    Okay, just reread your post you are not using the jack in the back. From what I can see PWR IN and BED PWR IN have all the grounds connected together, this is good practice, no floating grounds. The BED PWR IN +, I can't tell exactly how it is powered but I can say the + is connected to the HEATED BED + through the 15A fuse.

    The info I have is very limited, the board is a multi-layer controller board and the diagram I have had all the layers squished together, so if it isn't connected on the top layer it is very hard to see where things go. With the diagram I have it almost looks like BED PWR IN + is not connected through the power switch but I know that isn't true.
     
    #24 WheresWaldo, Dec 15, 2017
    Last edited: Dec 15, 2017
  5. colton81

    colton81 Active Member

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    Well I decided to give it a go.... unfortunately. I connected the bed power in to the same psu I’m using to power the main board and turned it on without the bed connected and the blue led underneath the bed power in pins was lit up. So I assumed I had it correct. But this is where something went wrong and hopefully didn’t destroy anything. I turned it off and then plugged in the bed, I switched it on and immediately the blue fuse blew. If I’m not mistaking the blue led should only be on when the board is trying to heat the bed correct? It seems like it blew because it shorted out like maybe the wires weren’t connected properly?


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  6. colton81

    colton81 Active Member

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    @Kilrah lol just saw your post about the fuse blowing... that’s exactly what happened but it blew before I could even try to test it.


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  7. colton81

    colton81 Active Member

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    I wish there was a way to bypass the onboard mossfett and use an external I think that might end up working. But I’m assuming everything is soldered in and isn’t possible


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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Trying to buck two different DC power supplies is usually a bad idea :) Even if they are the same voltage.
     
    Geof likes this.
  9. colton81

    colton81 Active Member

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    Its the same power supply I’m using for bot the heated bed and the power to the main board. I figured it really isn’t a good idea to try to use different power supplies that are connected together


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  10. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    The Robo board is so poorly documented and they messed with so many things that it isn't the best thing to repurpose for any other project. I know you don't want to hear this, but why not just buy a cheap Arduino / RAMPS combo kit. It would make your life infinitely easier.

    Or an all in one board like those sold by MKS, a lot of people resell these all over the world, even Amazon.
    MKS Base V1.5 (not an endorsement, just an example)
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    or a Smoothie board or a RAMBO, etc.
     
  12. Kilrah

    Kilrah Well-Known Member

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    What firmware are you running on the board?
    If it's not properly configured with heating bed control and the proper pins (you might want to use the R2 firmware) it's possible the relevant pin is always on.
     
  13. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    If there is an absolute need to repurpose the Robo Mainboard then he should be using my firmware and not the cluster that Robo calls Marlin.
     
  14. colton81

    colton81 Active Member

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    I’m pretty much just repurposing the robo board just to see if I can do it if it doesn’t work then I’ll switch to the other board I have.
    @WheresWaldo yea I am using your version of marlin and the mesh bed leveling works amazing.
    I think what I’ll do is just connect the bed up to the MKS board I have ( I believe that’s what it is) and just use that to control it. Is the only way to disable the heated bed is through the marlin firmware?


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