Using ATX PSU  

Re: Using ATX PSU

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Are there any drawback to using a ATX psu as powersource for the prusa i3 mk2 that I am overlooking ?
such a power supply is well eligible for powering the printer !
just make sure that you use cables with 2.5mm² conducting area when you connect the psu to the rambo board, especially for the branch that powers the heatbed (which draws 15amps).

another point to mention: the genuine psu of the i3 mk2 acts as a structural element of the frame assembly. so either leave the genuine psu assembled (which will age the psu artificial, due to the severe heat cycles inside the enclosure), or replace them by a "structural dummy", as the better solution.

Re: Using ATX PSU

...
Are there any drawback to using a ATX psu as powersource for the prusa i3 mk2 that I am overlooking ?
such a power supply is well eligible for powering the printer !
just make sure that you use cables with 2.5mm² conducting area when you connect the psu to the rambo board, especially for the branch that powers the heatbed (which draws 15amps).

another point to mention: the genuine psu of the i3 mk2 acts as a structural element of the frame assembly. so either leave the genuine psu assembled (which will age the psu artificial, due to the severe heat cycles inside the enclosure), or replace them by a "structural dummy", as the better solution.

Yes I would use 2.5mm² for the cables to the heat elements, also I am considering to use 2 SSR's to power the heatbed and nozzel to get the high currents away from the rambo board.

I also noticed that the psu is a structual component, but i coudl replace that with some metal work.

Re: Using ATX PSU

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Yes I would use 2.5mm² for the cables to the heat elements, also I am considering to use 2 SSR's to power the heatbed and nozzel to get the high currents away from the rambo board...

for the nozzle heater you don't need 2.5mm². The nozzle "only" draws approximately 3 ampere.... that's neither critical for the cable, nor a problem for the connector (and the n-channel mosfet). so you can keep the cable that is already attached to the heating element. just make sure that proper wire end ferrules are assembled at the end of the cables.

Re: Using ATX PSU

another point to mention: the genuine psu of the i3 mk2 acts as a structural element of the frame assembly. so either leave the genuine psu assembled (which will age the psu artificial, due to the severe heat cycles inside the enclosure), or replace them by a "structural dummy", as the better solution.

Is this a recommendation from Prusa? Or based on experience? When I built my heated enclosure I moved the PSU to the outside and didn't replace it with anything. I haven't had any issues with alignment, print quality, etc.

Re: Using ATX PSU

The Mk1 didn't connect the PSU to the Y axis, so I guess it's not critical

regards Joan

Re: Using ATX PSU

...Or based on experience? ...

it's just experience.
the frame is a little bit more instable when the psu is removed, especially when you've mounted a big spool holder on top of the frame, that can hold up to 3 filament spools at the same time (like I did).
no problem if you've moved your spool holder outside the enclosure.

Re: Using ATX PSU

In my case, I had not screwed down the "PSU-Y-Part", their name not mine. I gave up on remote system because all MK2S parts can handle up to 80°C including the plastics (all parts on mine are ABS) so didn't bother. What was a bother was my frame was leaned forward 2° due to prolonged spool holding and forgotten PSU screw-down after a mod. It also had visible pendulum movement on tall prints exacerbated by any "Ironing" feature due to the additional friction. Bent it back, screwed it down, moved all spools to top of chamber and all is well. As for my salvaged ATX PSU? Upcycled as automatic 14 140mm fan array.