In the recent MK3 review, I compared the heat up times of both the Prusa MK3 and MK2, and you might have noticed that small annotation I had with the MK2 being overvolted. A while ago, I had already published a video on how to do that and have your printer, any printer, really, heat up way faster and reach higher temperatures, but I pulled the video shortly after because it didn’t really have all the appropriate warnings attached to it. So before we start:
- This will void your warranty
- (damages from this process are easy to identify by the manufacturer)
- This process is not endorsed by Prusa or any other manufacturer
- I’m reaching into a power supply with a metal screwdriver, there could still be charged capacitors in there that might electrocute me -- or YOU, if you do the same
- There is a very real risk of frying your power supply, wiring, power transistors or heaters. If these components are undersized in your printer, they could even catch on fire.
- If you choose to do this, you’re doing it at your own risk. My MK2s have been running fine all this time with the voltage mod, but there’s no guarantee that it won’t turn your printer into a pile of ashes.
- DO THIS AT YOUR OWN RISK
Ok, are we clear here? Let’s go.
So the reason you might be doing this mod in the first place is because your printer’s heaters are just not quite powerful enough for what you want. That might be the heated bed not quite reaching the temperature you need for PETG or ABS, or it simply not being fast enough to get there -- something like the CR-10 actually takes like 30 minutes to heat up to 70°C, and even that is borderline too cold for PETG. On the early MK2 printers, the part cooling fan was too powerful to keep the hotend at temperature -- that’s fixed on the newer ones, and of course, the MK3, but it could still be something you see on your 3D printer as well.
But whatever your reasoning is, faster heatup times for the heated bed and the hotend are never a bad thing, right?
So what we’re going to do about that is to increase the power supply output voltage. This will in turn also drive more current through your heaters, so by just turning the voltage up 5% from 12 or 24V, you actually get 10% more power at the heater. It’s super easy to do, and in most cases boosts your heater power quite a bit -- what I’m about to show you on the first-generation MK2 has it output 36% extra power -- that means you can run the fan at full blast, or on something like the CR-10 with a heated bed which is just borderline powerful enough, you can use higher bed temperatures to print more materials or just spend less time waiting for your printer to get up to temperature. As a side effect, having more voltage in your 3D printer also makes the stepper drivers perform better, especially at higher speeds. So… let’s get to it!
So first things first, as always if you are working on any sort of electrical device turn of the power and wait a few seconds for everything to discharge inside. This mod we are about to do is also going to work on other machines that use similar styles of power supply but of course each machine is different in it´s own sort of ways your results might vary.
For the Prusa MK2 to remove the power supply from the frame you got the two screws in the back and these two M4 screws in the front here that hold it to the frame, next up you can remove the protected shroud from the power supply by undoing these three screws this large one in the back and these two smaller ones in the side. Once you got those unscrewed you can slide the powersupply conver off, but you dont have to slide it off all the way you just need to get it off far enough to expose the small hole in the top of the cover right there that hole lets you access the potesiometer that in turn adjust the output voltage of the entire power supply.
To adjust it you need to carefully reach in there with a flat head or a philips screwdriver making sure not to touch any of the components around it and by turning it clockwise you can increase the output voltage of the power supply. This one goes to around 13.7 volts but others goes over 14 or a bit lower if you dont want the full effect of this mod because your powersupply is at it’s limits already or you have electronics that may not handle the extra current simply dont turn it up that far or back off a bit one you reach the maximum.
My Prusa printers the maximum position works pritty well. As I like to say reassembly is the revers of disassembly so yeah do that once you get everything assembled again keep an eye on the power supply for a while to make sure that it stays cool to the touch, and altso maybe check on the electronics after a few minutes of printing just make sure that the output transistors are not getting to hot one other issue you might be running into is PID tuning of the heated bed and the hotend however we havent changed the output power to much so your old PID values if they where well tuned will usually still work but ofcourse you can always retune them and I’ve got an ancient video showing you how to do exactly that right up here and thats the entireley of the mod if this video helped you out by making your printer heat up a bit faster and hopefully didn’t damage to much.
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