RE: Power Supply failure
The power supply on my MK3/S just went out. I was printing PETG, which has higher temps than my usual PLA, therefor higher power requirements. I can think of several scenarios.
1. Statistical failure of defective components
2. Failure of Prusa to properly size the unit. Judging from the comments here, I am inclined to think this.
My question is: Is there a fuse on the power supply?
RE: Power Supply failure
OK, after searching in vain for a wiring diagram for the PS on Prusa sites, I found the answers elswhere. Not only was my PS fuse blown, but the PS itself is dead. All for running PETG instead of PLA.
Since this seems all too common for MK3 printers, I guess I will have to get a new supply. (8 months after US warranty dies.)
Any suggestions?
RE: Power Supply failure
For $35 you can get a 350 watt 24 volt PSU from Meanwell. Two day shipping. This does not count as a major calamity.
And there really have not been many reports of PSU failures here. Maybe you have a better set of numbers.
Now filament sensor problems and adhesion problems - those are common.
RE: Power Supply failure
@ben-g16
I'm using this PS since over one year without any problems: MEANWELL RSP-500-24
This has enough reserves and is only lukewarm when the bed and nozzle are heated (active ventilation). It is also cheaper than the Prusa PS.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
@karl-herbert
Thanks for all the suggestions. As I searched the web, I found many cases of failed power supplies. I sent a note to Prusa about my failure and got back a reply that it was out of warranty (USA warranty is 1 yr, Europe warranty is 2 yr) and I could buy one for $95 + shipping (25??).
I also noted I couldn’t find the replacement part on the web site. The note said "Our business is with printers, we do not intend to be a spare parts shop for everyone. That's why they are hidden." That seems like an oxymoron - ship bad power supplies, then hide the site for replacement parts.
Anyway, I looked up MeanWell power supplies and found a number of 350W 24 vdc versions. I chose the LRS-350-24 for $29 & free shipping from Amazon.
I decided to mount the PS directly on the side of the Mk3 frame at the top screw hole, then fit the switch and socket to the bottom. I cut the existing Adapter in half down the middle with a band saw and reused the parts to mount the supply. I printed one part to mate to the MeanWell frame.
I took the back part and used it to attach the bottom of ths PS to the rail. Note the vertical screw is off the old PS terminal - 4mm fit perfectly.
I made a matching part to fit the original cut up mount to the face and side of the MeanWell. Since there are no screw holes on the terminal side, I decided to make a spring catch that went inside the lowest vent slots to lock the mount and switch bracket in place. The final result is not pretty, but quite functional.
I printed the mating part using the left over PETG from my “S” conversion. That would test the performance of the PS. I forgot and left the 7.5A fuse in the fuse holder. The 350W PS requires a 15A fuse.. I was also in for nother surperise. The PTEG print values are 240ºF for the filament and 85ºF for the bed. As it was printing, I noticed the display showed 250ºF/90ºF. I don’t know why the MK3 ran that hot, but it should have blown the 7.5A fuse. Actually nothing happened and I got a good print. So, I am going to leave the fuse alone. My guess is the MeanWell is much more efficient and didn’t get to its current limit.
It is now printing PLA at the correct temps.
RE: Power Supply failure
To see spare parts, you have to be a registered owner and log into the EShop site.
Then the spare parts become visible.
RE: Power Supply failure
Sorry for the repeat - this site doesn’t deal with pictures correctly.
RE: Power Supply failure
@robert-rmm200
Couldn’t find the PSU on the site. The quote above from Prusa might explain why.
RE: Power Supply failure
Does seem a strange omission. I see the EINSY board, and even the frame - but no PSU.
I am guessing they are temporarily unavailable.
RE: Power Supply failure
@ben-g16
With the 350 Watt Meanwell you have made a good choice, and it is also much cheaper and more powerful than the Prusa power supply. I have been using Meanwell power supplies for many years and have never had any problems with them, provided they are handled properly. The only thing you have to do is design and print a new bracket. The powerpanic function also works with the meanwell.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
Erm - I also have the 350 watt Meanwell. How do you get power panic to function since the MK3S PSU has it integrated; not a separate board?
RE: Power Supply failure
@robert-rmm200
The main power panic circuit is on a PCB soldered to the back of the AC plug. The only connection between the power panic PCB and the power supply is a single wire it uses to get 24V from the power supply. So it was an easy transition.
Here an example of how to do it:
https://www.thingiverse.com/thing:3082178/comments/#comment-2058337
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
If you don't want to unsolder the board: https://www.oem3d.com/collections/electronics/products/mk3-power-panic-board-assembly
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
My only problem is that the MK3S, with the black PSU, has no power panic board. It is all integrated in the main board.
Good after-market item for someone.
RE: Power Supply failure
@robert-rmm200
integrated in the PSU mainboard? Anyway, i bought the powerpanic board (see pic. above) and integrated it to a selfmade case for my Meanwell. I did'nt try the board with fw 3.8.1, but i think it would work.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
Do you have a link for the board you pictured? That looks like a nice solution.
RE: Power Supply failure
In the US here: https://www.oem3d.com/collections/electronics/products/mk3-power-panic-board-assembly
Aliexpress: https://de.aliexpress.com/item/32929981990.html?spm=a2g0s.9042311.0.0.27424c4dX7zzTD (i bought it here).
here some informations: power_panic_replacement
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
Just contacted support and determined that the PSU is bad. Then they told me to kick rocks and buy a new PSU.
RE: Power Supply failure
@patrick-a7
I would think about buying this one: https://www.meanwell-web.com/en-gb/ac-dc-single-output-enclosed-power-supply-output-rsp--320--24
MK3 housing for this: https://www.thingiverse.com/thing:2863826
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Power Supply failure
After about 3 years of heavy use my 24v power supply died, PRPZ-24-240.
I heard a pop and thought I saw a flash out of the corner of my eye. Tested input voltage (120VAC - in USA) and output (nothing). After opening it up and looking around carefully I can't easily identify anything wrong. Was expecting to see a popped capacitor or transistor that let the smoke out. I'm no electrical engineer so I just ordered new power supply.
I went with a Mean Well LRS 350-24 (rated for 14.6A 24vdc output) for $30 delivered tomorrow instead of the Prusa for $100+customs fee and long lead times from COVID.
1. I'd be interested to know if anyone has been successful in repairing their power supply, I have other printers that I'd like to upgrade from MK2 to MK3 (12v to 24v) and I expect that it would be nice to have an extra on hand... and won't throw away perfectly good electronics if I can help it. Any help? A schematic? What went wrong with yours?
2. Has anyone has modeled printed parts for the Mean Well LRS 350-24. The part includes the switch, plug, and power panic board. I guess I'll be modeling it and posting it below if I don't hear from anyone.