Custom size mk3 heatbed


Hi Hawkeye

I put in instructions and so on in the first original post of this thread so that people can find info on how to go about getting a bed from me :slight_smile: The thread have become somewhat long and not easy to find the details for it.

Best Regards
Marlark aka Ted Dÿring



Would this (link) be a good second power supply for the bed?

I saw raby using a SP150 24volts from mean well, this one is the RS. The RS one costs half the price of the SP one.


Dont think it matters much. However 150 Watt is a little to weak. Need a little more amps for the task.


[quote=“Marlark”]However 150 Watt is a little to weak.[/quote]I agree : it’s OK for the standard MK3 Heated bed but not for Marlak’s.


Sorry for my short answer… I replied to this being a little mobile. Anyway as i wrote before … but sins the…

• Resistance at 24 Volt setting is around 2,6 Ohm

Is what the board is based on due to the extra size. Wish means you need at least 9,23A or a PSU at 24V that is at a minimum 221,52 Watt to run. Anything larger then that will do fine.

// Marlark



I’m not an electrical engineer so

can someone tell me why to choose the Mean Well RHS-320-24 PSU
instead of the Mean Well NES-350-24 PSU ?
or Mean Well SE-350-24 PSU ?

Cheers !


I dont think there is a huge diff on them in term of specifications. Looks more like a price issue against the extra Watt’s.


NHS and SE references are noted “discontinued” on the Meanwell website …


Any link or exact name for the 2-pin and 4-pin connector pin to be used for the main board?
I can find alot similar connectors from pictures, but is looking for the one with the best fit :slight_smile:

Edit: Found them on Ebay, search for: KF2510


Ahh so that is the name on them. Thx Norx


Hope those is close enough. Have a few in order to test. To bad ebay-sellers only lists 20+ each…
I only need one 2- and one 4-pin…


I’m getting all my parts installed, so when the heating bed comes in I will not have much to do. I’m at the point of installing the power expander and noticed on the back there are two pads to solder. Either inverted or normal. Do I solder one of them?


Those pads you dont touch for inverting. It is already configured correctly for this.


Thanks Marlark for that info.


Hey guys. i just began to set up the heatbed i just got from marlark. but i have to ask what size of the cables you are using. i took some speaker cables i had alredy. i belive they are 2.5mm2 but they get really hot during heatup. but because they get hot i belive they must be smaller.
i suppose that they should not get hot right?


Well I’m Using 2.5mm³ wires together with a 15VDC on the 12V Circuit and they get hot only when heating up and there’s much current flowing, after the plate reaches its temperature the cables cool back down. Works here so far…

Kind Regards


A PC’s internal power cables usually works good enouph. Is what i have used. When it comes for the signal cable from the mainboard to the PE i used the same type of cable that the stepper motors use. I run a 24V Circuit setup on mine.


okay. sounds good. i´ve got a modified server psu. rated for 12v 32a 400w thats enough right?

i might change the cables to some bigger ones just to be on the safe side.

i made the cables extra long to test everything beside the printer. that might be a factor to the heated cables.

and on another question. where in marlin do i change the preheat temp for the bed? and can i shut off the cooling fan during preheat?


[quote=“Hawkeye”]where in marlin do i change the preheat temp for the bed? [/quote]The answer to this is in the Wiki.

[quote=“Hawkeye”]can i shut off the cooling fan during preheat?[/quote]It doesn’t run during the bed Preheat.


[quote=“raby”][quote=“Hawkeye”]where in marlin do i change the preheat temp for the bed? [/quote]The answer to this is in the Wiki.

Thanks alot!.

then there is something wierd in my config. cause when i tell the printer to preheat the bed the the fan starts too.