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If i remove all voltage regulators and discard the switch and power jack could I put 24V into the UM shield? I know that for the hotend and HBP I would possibly need to take off the MOSFETs and put them onto a daughter board due to current issues and the tracks?

 

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You only need to replace the 7812, as that component will heat up to much (you need to replace it with a switching regulating one) everything else works fine on 24V

 

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Is it really that simple? I've brought a 24V PSU and a 12A DC DC buck step down voltage regulater and I did intent to use the buck to deliver 19V to the ultimaker but it may make more sense to set it to 12V and use it to replace the 7812 instead. This would also mean the 12V fan output will be able to deliver a lot more current?

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I don´t think so. For the fan output the limiting piece is not the 7812, but the transistor, if I remember correct. What kind of fans do you want to install? Running mine with a large cross flow fan, which does not draw much current... If you need more current than the transistor can deliver, you need to replace that one too.

 

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It is a 120 mm 12v 0,08A case fan to cool the ssr and buck. It doesn't have to be PWM controlled so I can draw the power directly from the buck. Are you sure the that fan that cools the pcb is controlled by a transistor? I thought it only was the 19V fan on the print head.

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Sorry, thought you meant the print had fan not the pcb fan. I am not sure about the electronics fan, but I think its not regulated at all and directly wired to 12V.

 

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The electronics cooling fan is 24V already and is undervolted.

The one you need to be careful of is the material cooling fan on the head. That one is 12V. However, contrary to the popular misconception that it is powered by 12V, it's not. It is powered by the raw input voltage which is normally 19V and considerably overvolting it already. At 24V PIN, you may burn out that fan.

 

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Note that I believe the current board runs the electronics cooling fan and the material cooling fan from Pin. Previous versions did have connectors for fans that cam off of the 12V regulator. The current version does not.

Get yourself a voltmeter and check. However, trust me when I say I tried a 12V fan for the material cooling and it instantly went up in smoke and I measured the full on voltage at 19.5V.

I don't have access to the schematic from where I am but look at it on UM's open source site. Pin is labelled VCC/2, Notice that VCC/2 is taken straight from the power connector. VCC/2 is what is send to both the material and electronics cooling fans.

On the current board, I believe the only thing that runs from 12V is the Arduino.

If you move to 24V, the things you need to be concerned about are:

The heater (probably OK as it is listed as 18V and controlled via PWM)

The 12V material fan currently driven at Pin will run at 24V (will probably burn out)

and a few LEDs (may burn out)

The heat from the 12V regulator if used.

As for the MOSFETs -The hotend heater MOSFET will probably be ok.

You might be able to use the HB MOSFET on board IF you use a heavy gauge jumper on the critical traces. I believe it is a low side switch so one leg goes to ground. Use a jump to that pin and connect to - on your 24V PS. The other pin goes to the screw terminal. Back that up with a jumper. The third (middle I believe but don't trust that, find a spec sheet or the schematic) other is the signal and you don't need to do anything with that. The other screw terminal is connected to VCC/2 which is Pin so use a jumper to connect it to + on the PS. Carefully monitor the connector to see if it is heating up due to the HB current.

 

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Hi!

Please keep us updated and - if it works - please post some detais/instructions :-)

I'm very interested in this mod...

Thanks!

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I reconfirmed that the 1.5.7 version powers ALL fans from Pin.

Callum, I think we discussed this before but you may have a weird prerelease version or simply an older version. The current 1.5.7 version does not have connectors off of the 12V regulator.

The only thing powered by the 12V regulator is the arduino.

Here is the schematic in enough resolution so you can see the labels. Note that VCC/2 is Pin and VCC is 5V.

http://ultimaker.ipbhost.com/uploads/gallery/album_699/gallery_33216_699_102360.png

 

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DISREGARD - THIS IS NOT THE L VERSION WHICH HAS THE BENT PINS.

REGARD - The correct L part is -

http://www.mouser.com/ProductDetail/RECOM-Power/R-78B12-10L/?qs=sGAEpiMZZMt6Q9lZSPl3RfQvc4xooI3I%252by2zpaVmQHw%3D'>http://www.mouser.com/ProductDetail/RECOM-Power/R-78B12-10L/?qs=sGAEpiMZZMt6Q9lZSPl3RfQvc4xooI3I%252by2zpaVmQHw%3D

If you wanted to replace the regulator with a switching version compatible with higher input voltage, this one might be ideal:

(updated to the L version).

http://www.mouser.com/ProductDetail/RECOM-Power/R-78B12-10L/?qs=sGAEpiMZZMt6Q9lZSPl3RfQvc4xooI3I%252by2zpaVmQHw%3D

 

Contrary to the picture on Mouser's site, it is the horizontal version but still might require clearancing the cover. It is pin compatible with the linear regulator and can supply 1A.

No guarantee however....

 

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Yes, the additional wire is for the tachometer output. However, the issue is that the 3 wire connector won't plug into the 2 wire connector at the end of the cable on the print head.

So you can either cut it off and the one on the cable and solder together and shrink warp or tape or cut the one off of the fan and source a 2 pin connector and solder it on

Or you can point your browser to the version with the compatible connector.

 

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