Power Supply failure  

Re: Power Supply failure

The wiring harness is simple. Go to your home improvement store and buy some 14-16 gauge power cord wire and buy some male and female spade connectors. Everything else is reusable.

Christopher ...

Replacing the pair of power cables from the PSU to the Einsy is straight-forward, and I have the parts in stock. Lengthening the black&white power panic cable will require a little more work, since it's soldered to the power panic board on one end, and connectorized on the other. Not impossible, or even particularly daunting, but also not as easy as unplugging cables from one power supply and plugging them into another.

- Craig -

Re: Power Supply failure

Hi there,
Well the PSU on my 2 weeks old i3 MK3 just died yesterday during a PET print and managed to pop our mains breaker at the same time.
Having read the full thread it seems that the stock PSU is garbage and underrated.
I have contacted Prusa for assistance but it seems I will order a silent meanwell HEP-320-24A PSU to use instead. These are costly but powerful and dead silent. Also I will be more confident leaving the 3D printer running unattended.

For all these comments regarding CE certification : this is a safety certification . A product can pass CE certification but can still be crap and fail on you. In other words CE is not a quality certification. BTW I wonder how the whole printer passed CE certification by using (non flame retardant ?) 3D printed parts around the PSU and mains socket.

Side note : I have also been experiencing layer shifting multiple times with this printer.
This printer prints well when it does actually print...
So far not impressed at all with this printer. Thankfully my trustworthy BCN3D sigma is here.

Re: Power Supply failure

The pulse modulation seems an odd reason. The PWM rate would be nowhere near the frequency of the clicking form what I’ve heard. I’ll let them do their thing though.

I have an MIT engineer friend. If mine fails when it comes maybe I can show him and help everyone out.

I wouldn't call it PWM. The frequency of the clicking is the rate at which the heated bed relay is turning on and off. This is controlled by the PID algorithm (or maybe it is just on/off, which is worse). This appears to cause large/sudden swings in PSU current (3 ohms @ 24v, so possibly switching from 0 to 8A and back). Changes in current lead to strong magnetic fields which can cause physical movement/vibration somewhere in the PSU. Hence the clicking.

It is clear this is happening because the clicking aligns with the heated bed LED timing.

Re: Power Supply failure

OK, i agree that it's physics. But i also know that this physics can be silenced. That's why some coils are submerged in resin to eliminate clicks. Better / more precise manufacturing and better quality core materials also causes clicks to go away. But having more expensive PSU would increase total cost of printer.

Agreed, I don't hear any clicking when using my MeanWell PSU.

Re: Power Supply failure

He everyone.

Just want to add another information point.

I now have nearly 4 days solid printing on my mk3 with zero issues. I’m printing on PLA only at the moment. And I’m on 240v as most will know.

I still firmly think that the issue is a 240v / 110v issue.

Jason.

Re: Power Supply failure

Hi there,
Well the PSU on my 2 weeks old i3 MK3 just died yesterday during a PET print and managed to pop our mains breaker at the same time.
Having read the full thread it seems that the stock PSU is garbage and underrated.
I have contacted Prusa for assistance but it seems I will order a silent meanwell HEP-320-24A PSU to use instead. These are costly but powerful and dead silent. Also I will be more confident leaving the 3D printer running unattended.

For all these comments regarding CE certification : this is a safety certification . A product can pass CE certification but can still be crap and fail on you. In other words CE is not a quality certification. BTW I wonder how the whole printer passed CE certification by using (non flame retardant ?) 3D printed parts around the PSU and mains socket.

Side note : I have also been experiencing layer shifting multiple times with this printer.
This printer prints well when it does actually print...
So far not impressed at all with this printer. Thankfully my trustworthy BCN3D sigma is here.

110 or 220V?

Re: Power Supply failure

Hi there,
Well the PSU on my 2 weeks old i3 MK3 just died yesterday during a PET print and managed to pop our mains breaker at the same time.
Having read the full thread it seems that the stock PSU is garbage and underrated.
I have contacted Prusa for assistance but it seems I will order a silent meanwell HEP-320-24A PSU to use instead. These are costly but powerful and dead silent. Also I will be more confident leaving the 3D printer running unattended.

For all these comments regarding CE certification : this is a safety certification . A product can pass CE certification but can still be crap and fail on you. In other words CE is not a quality certification. BTW I wonder how the whole printer passed CE certification by using (non flame retardant ?) 3D printed parts around the PSU and mains socket.

Side note : I have also been experiencing layer shifting multiple times with this printer.
This printer prints well when it does actually print...
So far not impressed at all with this printer. Thankfully my trustworthy BCN3D sigma is here.

110 or 220V?

I'm in France : so 230V

Re: Power Supply failure

[/quote]

110 or 220V?

I'm in France : so 230V
[/quote]

Thanks - that's the first "non-110V" failure report I recall seeing here.

Re: Power Supply failure

Just removed the faulty PSU and hooked up my lab PSU.
Started a PET print (260/90 degrees) and the current consumption maxes my PSU at 10 Amps (24V) when the bed starts to heat.
Once the BED gets warmer the current drops to 8 Amps.
Once the print has started the current draw caries a lot between 2 and 7 amps.

Re: Power Supply failure

Well, you can add me to the list of MK3 owners with a failed power supply (located in the U.S., so 110V).

The unit actually failed over a week ago, and I've been trying to get Prusa to sent a replacement supply all last week. As of now, they have not committed to sending me a replacement.

They may be busy, but I am certainly getting frustrated with their lack of responsiveness on the PSU issue. I initially sent and e-mail indicating a problem. No response. So I then did an on-line chat. During the chat session, they had me do basic troubleshooting. They had me check fuses on the Rambo board (they were all ok). I could tell them that the problem is in the PSU, as we had 0 VDC coming out of it (after confirming a good fuse on the AC side and verifying that I had the thing plugged in and the switch in the correct position).

The chat session ended with a request for a follow-up email from me detailing what we confirmed during the chat and some photo documentation. They promised that they would take action the next day. I submitted the documentation package and waited. No response.

So, I generated another e-mail - and received a response from a different customer-support person. Now, saying that I can't measure the DC output voltage with the Rambo still connected to the PSU. So, redo the trouble-shooting, and by the way, can you provide video documentation of what you did.

So, yes, I disconnected the Rambo board and once again checked the output voltage from the PSU. Guess what, it's still 0 VDC when it's receiving 120 VAC on the input terminals. And yes, I took a video of me doing all of this and sent it to them. Do you know what a PITA it is to hold a cell phone camera in one hand while probing PSU terminals with two probes in the other? I guess I'm a better man for it. 😉

That was last Thursday. I pinged them again on Friday. Nothing. I pinged them again today. Nothing.

Is this type of responsiveness and requests for pictures and video consistent with other's experiences?

Any suggestions as to what I can do to better manage getting a replacement is appreciated.

Re: Power Supply failure

I consider this so much of an issue that even though i dont have a printer yet i ordered a 24V 20A unit to use if the stock one fails. I want to avoid any downtime if possible so wanted a beefed up unit on hand.

Re: Power Supply failure

I did exactly the same. I have a Meanwell NES 350W 24 coming as a backup. Just need to print the holder for it that was designed and shown in this thread.

Which I should do sooner rather than later.
Can’t print it after the failure (if it happens)

By the way, I’m now at nearly 300 hours of print time and no issues as yet. Maybe I got a good one. Who knows ? Either way I’m prepared to replace the PSU should the need arise.

Jason.

Re: Power Supply failure

Is this type of responsiveness and requests for pictures and video consistent with other's experiences?

Any suggestions as to what I can do to better manage getting a replacement is appreciated.

No, this seems excessive. My first fail I explained what had happened (fail mid-print) and my basic trouble shooting (remove PSU from base, directly wire 120v, 0VDC on outputs.) They then mailed me a new one (although it took them 4 days to ship it so it was more than a week later).

My second one I started the conversation with video of the voltage dropping to 0v when the heat-bed kicked in, resetting the Einsy, and then popping back to 24V. I happened to have that because it was so unusual I needed to debug it to figure out what was going on.

So: in both cases I had pretty convincing evidence so I may have avoided the 3rd degree.

Paul

Re: Power Supply failure

Is this type of responsiveness and requests for pictures and video consistent with other's experiences?

Any suggestions as to what I can do to better manage getting a replacement is appreciated.

No, this seems excessive. My first fail I explained what had happened (fail mid-print) and my basic trouble shooting (remove PSU from base, directly wire 120v, 0VDC on outputs.) They then mailed me a new one (although it took them 4 days to ship it so it was more than a week later).

My second one I started the conversation with video of the voltage dropping to 0v when the heat-bed kicked in, resetting the Einsy, and then popping back to 24V. I happened to have that because it was so unusual I needed to debug it to figure out what was going on.

So: in both cases I had pretty convincing evidence so I may have avoided the 3rd degree.

Paul

Thanks Paul. No response as of 8 AM this morning local. Once I started seeing how this was going I did order the Meanwell PSU. I have it wired up so I can print - but I'd either like to get a working replacement PSU from Prusa or at least reimbursed for my out of pocket cost to acquire the Meanwell.

Rick

Re: Power Supply failure

or at least reimbursed for my out of pocket cost to acquire the Meanwell.

Don't hold your breath on that one...my guess is that PRUSA's wholesale cost on the PSU, plus shipping, is less than you paid for the Meanwell 😉

I don't see why they wouldn't send you a stock replacement though.

Re: Power Supply failure

or at least reimbursed for my out of pocket cost to acquire the Meanwell.

Don't hold your breath on that one...my guess is that PRUSA's wholesale cost on the PSU, plus shipping, is less than you paid for the Meanwell 😉

I don't see why they wouldn't send you a stock replacement though.

Ok, just finished another chat session. They are sending me a replacement supply. Finally! I most likely will keep it as a spare in case my Meanwell ever fails.

Re: Power Supply failure

I got my replacement supply a week ago, and its working, ive been doing 24+ hour prints and making sure it wont die soon (i hope). One thing i have noticed is the temperature of the PSU gets really hot on both PLA and PetG prints. I have hooked up a 40mm fan that i had sitting around, and ran power to it. The PSU is noticeably cooler now and I have a feeling that it will last longer due to the heat not affecting internal components. I plan on getting an 80mm noctua and using/modifying a mount and some kind of 12v power supply (noctuas are just 12v as far as i can tell).

Re: Power Supply failure

I would just like to add myself to the list of PSU failure. I received my MK3 late Jan and have been working on small prints calibrating as I have time. Yesterday I finally got it to a point where I started to put it through it paces pushing several 4 hr prints through it one after another when towards the end of the day the supply failed. When I saw it die It did have a slight smell of burnt components and it did pop the internal fuse. I promised Prusa support I would not open it so I don't know exactly what failed internally at this point. Prusa is sending me a replacement... Not sure how long it will take. I have been following this specific forum since it started and I have been concerned whether this was a rampant problem or not. I don't think it is because I can see the posts of Prusa's farm running MK3 all seem to have the same supply and I would hope if there was a huge problem with these supplies that they would have provided an alternative at this point. But on the other hand this issue does seem to affect quite a few users. Hopefully those that get replacements will not see recurrences of this issue and can chalk it up to bad luck....

Re: Power Supply failure

I don't think it is because I can see the posts of Prusa's farm running MK3 all seem to have the same supply and I would hope if there was a huge problem with these supplies that they would have provided an alternative at this point.

Sorry to hear about your PSU burn.

I don't think that is compelling evidence even on an anecdotal level, as the failures seem to only be prevalent for 110v users (PRUSA is in Prague, so 240v). I have to assume that if they were operating at 110v, or even doing substantial testing at 110v, they would have caught whatever the design/manufacturing problem is before it reached this point.

Re: Power Supply failure

I recently completed a 12 hour print with PLA and performance was 100%. I have 3+ days on the MK3 runtime meter thus far.