Power Supply failure  

Re: Power Supply failure

Has anyone located the 3D model CAD for the power supply plastic lower AC cover yet?

Re: Power Supply failure

There is a power supply cover in the MK2 branch on GitHub, but unknown if this will also fit the 24V PS on the MK3.

Re: Power Supply failure

Hi all. I too noticed brownouts during printing to begin with. Inmediately decided to order a PSU with a bit more power.
Ordered this one from Reprapworld https://reprapworld.com/products/electronics/power_supply/power_supply_24v_240_115v_15a_max/ . Printing PETG like a charm now. Here is a chassis part in .stl I made with which you can use the original switch and mains connector. Fixing it to the metal frame is indeed not easy. Tapped a new hole for the top screw in the unit, but the bottom one fell short. Feels properly secured anyway.

Re: Power Supply failure

I'm still waiting for MK3 and watching this issue. So I do some research and made a summary:

Prusa Original PSU:
- 24 V / 10 A / 240 W
- no active cooling
- unreliable supplier (inconsistent quality, different components - better/worse)
- most of the time is sufficient, but at some cases is more stressed on the edge of its performance
- includes power factor correction (PFC) and many protection like over temp, over current/shorts as well

Einsy Rambo 1.0a:
- recommended power supply directly by Ultimachine: 16A+ which corresponds simply to 380+ W PSU
- HB fuse has nominal value 15 A, so it doesn't make sense if the PSU can supply only 10 A

The question is: is the PSU underestimated? I guess, that PR definitely did their research and real tests, so according to average consumption it works pretty well. It can be fixed in firmware, but on the other hand, it is alaways better to design limit by HW for best performance and safety at the worst case scenario.

Re: Power Supply failure

PR CSR replied to my email/yt vid on the clicking:

Hello Guy.

Hello Guy.

Thank you for your email.

This clicking is known to us and you don´t need to worry about it. It is coming half way from the PSU and half way from the heat bed due to "vibrating" magnets.

Kind Regards,

—
Peter Mencák
Customer Support

PRUSA Research
+420 222 263 718
+421 220 570 305
188/7a Partyzánská, 17000, Prague
shop.prusa3D.com

For simple troubleshooting, please use: http://help.prusa3d.com

On Mon, Jan 15, 2018 at 07:34 pm, <> Guy wrote:
My power supply is making a clicking noise at times during printing. Is this normal?

Here’s a short video of the clicking:

Sent from Mail for Windows 10

Re: Power Supply failure

Hi all. I too noticed brownouts during printing to begin with. Inmediately decided to order a PSU with a bit more power.
Ordered this one from Reprapworld https://reprapworld.com/products/electronics/power_supply/power_supply_24v_240_115v_15a_max/ . Printing PETG like a charm now. Here is a chassis part in .stl I made with which you can use the original switch and mains connector. Fixing it to the metal frame is indeed not easy. Tapped a new hole for the top screw in the unit, but the bottom one fell short. Feels properly secured anyway.

You will lose your power panic functionality one would guess unless you know how to wire up a similar circuit to the original, or am I missing something?

Re: Power Supply failure

Hi all. I too noticed brownouts during printing to begin with. Inmediately decided to order a PSU with a bit more power.
Ordered this one from Reprapworld https://reprapworld.com/products/electronics/power_supply/power_supply_24v_240_115v_15a_max/ . Printing PETG like a charm now. Here is a chassis part in .stl I made with which you can use the original switch and mains connector. Fixing it to the metal frame is indeed not easy. Tapped a new hole for the top screw in the unit, but the bottom one fell short. Feels properly secured anyway.

You will lose your power panic functionality one would guess unless you know how to wire up a similar circuit to the original, or am I missing something?

Power panic PCB is soldered right behind the power socket, so it is not a big deal, but you have to know what you are doing due to dangerous voltage 110 V /230 V.

Re: Power Supply failure

I'm still waiting for MK3 and watching this issue. So I do some research and made a summary:

Prusa Original PSU:
- 24 V / 10 A / 240 W
- no active cooling
- unreliable supplier (inconsistent quality, different components - better/worse)
- most of the time is sufficient, but at some cases is more stressed on the edge of its performance
- includes power factor correction (PFC) and many protection like over temp, over current/shorts as well

Einsy Rambo 1.0a:
- recommended power supply directly by Ultimachine: 16A+ which corresponds simply to 380+ W PSU
- HB fuse has nominal value 15 A, so it doesn't make sense if the PSU can supply only 10 A

The question is: is the PSU underestimated? I guess, that PR definitely did their research and real tests, so according to average consumption it works pretty well. It can be fixed in firmware, but on the other hand, it is alaways better to design limit by HW for best performance and safety at the worst case scenario.

Perhaps Ultimachine was saying that they recommend a 200+ Watt power supply assuming on the low end 12V 16A. That was my takeaway from it.

Re: Power Supply failure

Hi all. I too noticed brownouts during printing to begin with. Inmediately decided to order a PSU with a bit more power.
Ordered this one from Reprapworld https://reprapworld.com/products/electronics/power_supply/power_supply_24v_240_115v_15a_max/ .

I'm afraid that you might experience similar problem as with original one. I have some experience with quality and "chinese" PSU's. Hopefully not... But price is suspiciously low.... meanwell PSU is in price range of 60-70 euro. If i will purchase my own PSU i will definitely buy a quality one from well-known company.

Re: Power Supply failure

Prusa Original PSU:
- 24 V / 10 A / 240 W
...
Einsy Rambo 1.0a:
- recommended power supply directly by Ultimachine: 16A+ which corresponds simply to 380+ W PSU
- HB fuse has nominal value 15 A, so it doesn't make sense if the PSU can supply only 10 A

The question is: is the PSU underestimated? I guess, that PR definitely did their research and real tests, so according to average consumption it works ....

If you really want to calculate something, add power rating of heat bed and hotend, which are the main contributors, and compare this to the PSU spec. The problem is that the heatbed probably has no proper spec as it is made by PR. Also, I assume the heatbed consists of a regular copper-clad PCB, which means it has a positive thermal coefficient (higher power when cold). Also I assume a PCB heating to have quite a bit of tolerances, as copper thickness and trace width won't have narrow tolerances. Motor power (not current) consumption is much more difficult to predict (the motor controllers are current regulated, but coil voltage depends on motor back EMF etc). Overall I'd consider this a waste of time. If you don't trust the PSU, connect a voltmeter to the output and see if the PSU keeps its 24V nominal. If there is any problem, the voltage will drop. If you are really curious, connect a logger or scope or both.

Regarding the fuse: A rating of 15 A does not mean it blows at 15.01 A. Find a datasheet and look at the curves. Basically a 15 A fuse sure blows quickly at 30 A - that's what it is made for, to protect against fire in case of a catastrophic failure (short circuit). I am not sure if a 15 A fuse blows at all connected to a 10 A supply as the PSU itself will most likely have numerous protections in place (like overcurrent).

- Martin

Re: Power Supply failure

If you really want to calculate something, add power rating of heat bed and hotend, which are the main contributors, and compare this to the PSU spec. The problem is that the heatbed probably has no proper spec as it is made by PR. Also, I assume the heatbed consists of a regular copper-clad PCB, which means it has a positive thermal coefficient (higher power when cold). Also I assume a PCB heating to have quite a bit of tolerances, as copper thickness and trace width won't have narrow tolerances. Motor power (not current) consumption is much more difficult to predict (the motor controllers are current regulated, but coil voltage depends on motor back EMF etc). Overall I'd consider this a waste of time. If you don't trust the PSU, connect a voltmeter to the output and see if the PSU keeps its 24V nominal. If there is any problem, the voltage will drop. If you are really curious, connect a logger or scope or both.

Regarding the fuse: A rating of 15 A does not mean it blows at 15.01 A. Find a datasheet and look at the curves. Basically a 15 A fuse sure blows quickly at 30 A - that's what it is made for, to protect against fire in case of a catastrophic failure (short circuit). I am not sure if a 15 A fuse blows at all connected to a 10 A supply as the PSU itself will most likely have numerous protections in place (like overcurrent).

- Martin

Thanks for your post, Martin. That is all what I know. Anyway the MK2S has average power consumption (70 / 110) W for PLA / ABS and I don't expect that MK3 is significantly different, so 240 W PSU should be OK. I hope that these failures were caused only by faulty pieces.

Regarding the fuse: I don't say it is useless at all. Better an oveprotection than sorry, but I expected that protections will be sorted in a cascade, that's all.

Re: Power Supply failure

I just wish that Josef Prusa could come out and say that either this is not an issue or it's a bug that we're working on fixing and anyone impacted will get a free replacement PSU. There are so many bug threads out there that could get squashed by a little communication. Would definitely help to put his customers at ease who may or may not be willing to buy future upgrades and new models (hint hint)

Re: Power Supply failure

So I built my printer yesterday. I ran one single print which failed right at the end due to thermal runaway (no idea what that is) and there were skipped steps: check my thread for info on that.

I restarted the print and it failed almost immediately, tried again, failed again, printer kept rehoming and restarting. I turned it off and turned it back on and I was met with a flickering screen and no start up. Checking with a multimeter and : yeah. So I assume the power supply is done. Speaking to support right now so hopefully I can get it sorted.

This is my first ever printer and while I am sad it isn't working, support have been really nice to deal with and helpful when I got stuck building, it's just a shame for what, to me anyway, is a lot of money, I'm having problems. First an incorrect thermistor shipped with it, a replacement was sent (but with no instructions of how to fit it, thankfully it wasn't hard at all) and now this. Fingers crossed it can be sorted.

Perhaps the kit should be offered with the ability to connect your own computer PSU with a couple of resistors and a 21pin start up adaptor or similar.

Update: Support is sending me a new PSU. I plugged the printer back in and I've gotten it to start another print but when the temp dropped and the heater ramped up the printer died again. I've also noticed that while heating there is a whining noise coming from the rambo...that's right, the rambo?! At first I thought it was the fan squeaking, it sounds like that kind of noise but no, its coming from the electronics box. No idea what that is but that is the end of testing for me with this PSU. I will wait and see what happens when the new one arrives.

Re: Power Supply failure

Has anyone located the 3D model CAD for the power supply plastic lower AC cover yet?

No. I brought up the one in the mk2 area in openscad, but it is clearly different. My mk3 PSU base has a removable bottom, but the mk2 scad file has a solid base.

There is no comparably named PSU part in the scad directory of the i3 github. I'll add a request for that scad file to my PSU support thread with PRUSA. I'd like to use it as a starting point for my new PSU attach.

Re: Power Supply failure

Just noticed RC5 Firmware is online @ https://www.prusa3d.com/drivers/#firmware

One change of note...not sure if this is related to people having issues with their PSU blowing...

Bed temperature runaway implemented

Re: Power Supply failure

When someone gets time could you please get the dimensions of the MK3 Prusa power supply without the black plastic cover.

Thanks!

Re: Power Supply failure

When someone gets time could you please get the dimensions of the MK3 Prusa power supply without the black plastic cover.

Thanks!

Here you go. I captured the general shape, and only the holes used by the mk3.

2 holes tapped 4mm to attach to the frame side (first image)
2 holes tapped 3mm on back (towards the einsy side) for attachment to the 3d printed part
1 hole tapped 4mm on the side toward the back of the printer.

Overall dimensions 99.75 x 49 x 200 (I triple checked the 99.75, but I suspect it's supposed to be 100 with a bit of slop)

https://imgur.com/a/rGnm8

Re: Power Supply failure

When someone gets time could you please get the dimensions of the MK3 Prusa power supply without the black plastic cover.

Thanks!

Here you go. I captured the general shape, and only the holes used by the mk3.

2 holes tapped 4mm to attach to the frame side (first image)
2 holes tapped 3mm on back (towards the einsy side) for attachment to the 3d printed part
1 hole tapped 4mm on the side toward the back of the printer.

Overall dimensions 99.75 x 49 x 200 (I triple checked the 99.75, but I suspect it's supposed to be 100 with a bit of slop)

https://imgur.com/a/rGnm8

Thanks! Paul

Great job! I didn't expect to get CAD prints....wow.

Here is some dimension specs for the Meanwell power supplies.

Looks like none of these Meanwell supplies have the same mounting screw hole locations but the 240 case could fit the Prusa MK3 supply plastic end cover opening. Not sure on the attachment hole locations to screw on the plastic cover.

Meanwell SP-240W 24V/10A spec sheet, case size 190x93x50: http://www.meanwell.com/Upload/PDF/SP-240/SP-240-SPEC.PDF
Meanwell SP-320W 24V/13A spec sheet, case size 215x115x50: http://www.meanwellusa.com/webapp/product/search.aspx?prod=SP-320

Meanwell NES-350W 24V/14.6A spec sheet, case size 215x115x50: http://meanwellusa.com/productPdf.aspx?i=457#1
Only UL (USA) rated (Not CE or TUV)

If I personally were in need of a new supply I would consider the SE-320-24 (312W rated) or the NES-350-24 and make it fit with a new designed end cover and frame holes.

I am not making any recommendations to use anything that is not Prusa approved. Use at your own risk with your own judgment.

Re: Power Supply failure

I started to measure my bare Prusa PSU and sketch it, but realized describing all the hole locations in text or sketching it by hand and taking a picture were both much harder than just spending 5 minutes entering into Fusion 360 and taking a few screen shots. I also realized I was possibly the only one on the forum who actually has my Prusa PSU out of the black base, available for measurement, and not yet shipped back to Prusa for replacement. I therefore couldn't assume somebody else would do it.

Agreed, the MeanWell 350 I bought is 15mm taller, 15 wider, but about the same thickness (50 vs measured 49, likely specced at 50), and has holes in different places/sizes.

The back/side holes don't matter (I can easily redesign the 3d printed part to handle that). The holes flush to the frame are a bigger deal. They are tapped 6mm, and are too high on the part and too far apart to match the holes in the frame. I don't want to modify the frame if I can avoid it.

Likely what I'll do is print a PETG base that fits the bottom, and a 5mm thick PETG "adapter" that fits between the new PSU and the frame. It'll have holes with slots for 4mm nuts where the current frame holes are, and 6mm holes where the PSU has holes. If that's not stiff enough, I'll have to add a bit more structure to the shim. Fortunately the nuts in the y-extrusion are loose, so I should be able to move the base support a bit further back with no issue.

I asked Prusa if the scad file for the original PSU base was available. Support indicated he didn't think it had been posted, but he'd ask around. I'm hoping they'll post it so I can start with that.

Re: Power Supply failure

I was about to go and cancel my order, not too happy with the power supply problem and talked to tech support last night and tech support does not think that the clicking noise coming out of the power supply is a problem 😥 , even with all the power supply failures being reported. But my order just got changed from Backorder to Oder Being Packed, might be too late to cancel the order now. Should have canceled the order this morning (3 hours ago) when it was still on "Backorder". I guess I'll just hope my house does not burn down or Prusa does not get sick of sending me a new power supply when one fails.