Power Supply failure  

Re: Power Supply failure

I've read so far resistor, thermistor and blown fuse. Doesn't sound like "one component is failing"- design issue. It may be also a bad batch or any other reason which brings the PSU to the limit where it's failing.

Just to be clear. I also think the PSU is operating at the limit and PR need to take action on that.

Re: Power Supply failure

I think i found my issue

Re: Power Supply failure

That resistor died for a reason - it's not cause of the problem, but rather the consequence... one semiconductor died (transistor, diode...) and as a result this resistor was blown.

Re: Power Supply failure

Antonio, Are you pointing out the transistor R4 or the white glob on the right? For a new power supply a few of those areas look like it's been used for years.
Where is that white glob coming from?

Re: Power Supply failure

Antonio, Are you pointing out the transistor R4 or the white glob on the right? For a new power supply a few of those areas look like it's been used for years.
Where is that white glob coming from?

R4 is a resistor.. and it would have blow due to another failure, somewhere on the board.

The “glob” is just some kind of elastic sealent, placed on components to stop vibrations or to insulate.

Re: Power Supply failure

Antonio, Are you pointing out the transistor R4 or the white glob on the right? For a new power supply a few of those areas look like it's been used for years.
Where is that white glob coming from?

R4 is a resistor.. and it would have blow due to another failure, somewhere on the board.

The “glob” is just some kind of elastic sealent, placed on components to stop vibrations or to insulate.

jweaver, thanks for the correction. I KNEW THAT..... I guess I was/am still asleep.

Re: Power Supply failure

I designed a PSU cover for both the Mean Well NES-350 and it's replacement the LRS-350. It mounts exactly like the stock power supply so it keeps the same sleek look. Feedback is always welcome. Hope this helps.

https://www.thingiverse.com/thing:2812350

Re: Power Supply failure

I designed a PSU cover for both the Mean Well NES-350 and it's replacement the LRS-350. It mounts exactly like the stock power supply so it keeps the same sleek look. Feedback is always welcome. Hope this helps.

https://www.thingiverse.com/thing:2812350

Cool design, thanks for sharing!

As you discovered, the biggest hassle is that the PSU holes don't line up with the frame holes. I experimented with the same idea (solid printed shim with holes for both), but ended up offsetting my PSU to the side instead, and leaving a simple brace between Y and Z axis.

I ran into the same collision with the back of the y-frame and had to do a similar notch (actually, in my case I just made the bottom plate shorter and adjusted the PSU box accordingly.

It's entertaining seeing somebody else tackling the same issues. Good work.

Did you do it in openSCAD? If so, can you post the files? If not, I'm curious what tool you used? I thought about doing it in fusion360 (would have been easier!) but I liked the idea of making it easier for people to tweak my design if I screwed it up.

BTW, are you just living with the meanwell 350 fan noise every now and then? Or did you fix it in some way?

Re: Power Supply failure

I designed a PSU cover for both the Mean Well NES-350 and it's replacement the LRS-350. It mounts exactly like the stock power supply so it keeps the same sleek look. Feedback is always welcome. Hope this helps.

https://www.thingiverse.com/thing:2812350

Cool design, thanks for sharing!

As you discovered, the biggest hassle is that the PSU holes don't line up with the frame holes. I experimented with the same idea (solid printed shim with holes for both), but ended up offsetting my PSU to the side instead, and leaving a simple brace between Y and Z axis.

I ran into the same collision with the back of the y-frame and had to do a similar notch (actually, in my case I just made the bottom plate shorter and adjusted the PSU box accordingly.

It's entertaining seeing somebody else tackling the same issues. Good work.

Did you do it in openSCAD? If so, can you post the files? If not, I'm curious what tool you used? I thought about doing it in fusion360 (would have been easier!) but I liked the idea of making it easier for people to tweak my design if I screwed it up.

BTW, are you just living with the meanwell 350 fan noise every now and then? Or did you fix it in some way?

I did this all in Fusion 360. I plan on releasing the files but am tying to clean up my project. To silent the fan, I used the low noise adapter that came with my Noctua fan. I cut it up and soldered it inline. It makes a huge difference and the fan doesn’t really run much longer. There’s still plenty of airflow. I would have loved to use a Noctua, but unfortunately they are too tall by just the teeniest amount lol

Re: Power Supply failure

I would have loved to use a Noctua, but unfortunately they are too tall by just the teeniest amount lol

I hear you. I bought that Noctua and installed it, but it just barely hits a cap on the board. What a pain.

When I get the chance, I'm just going to flip it around and install the fan on the outside of the case. For now, I'm using the stock loud fan.

Re: Power Supply failure

I would have loved to use a Noctua, but unfortunately they are too tall by just the teeniest amount lol

I hear you. I bought that Noctua and installed it, but it just barely hits a cap on the board. What a pain.

When I get the chance, I'm just going to flip it around and install the fan on the outside of the case. For now, I'm using the stock loud fan.

It was SOOO close, but yeah, that one capacitor was in the way. I thought about mounting it on the exterior too but after trying the resistor, It really wasn't necessary. I'll save the Noctua for a later project.

Re: Power Supply failure

Another one bites the dust. 120V 45ish days printing time. Printer was preheating. Dark room saw a flash, printer lost power, fuse blown and a resistor looks like someone took a chisel to it.

Replacement on the way from Prusa.

At this time I don't feel like I should have to buy a 3rd party PSU.

Kinda irritated with the downtime as my printers have a backlog right now.

Re: Power Supply failure

Another one bites the dust. 120V 45ish days printing time. Printer was preheating. Dark room saw a flash, printer lost power, fuse blown and a resistor looks like someone took a chisel to it.

Replacement on the way from Prusa.

At this time I don't feel like I should have to buy a 3rd party PSU.

Kinda irritated with the downtime as my printers have a backlog right now.

I am also a bit disappointed with Prusa on the PSU issue. With all the complex things that can and do go wrong with a 3d printer, the PSU should just be rock solid. I've got enough other issues to worry about.

It seems like they went marginal on the PSU selection. Maybe they've had good luck with this supplier on 12V PSUs, but it isn't translating to 24V.

In my case, I don't trust their replacement PSUs (having had two dead PSUs so far), so I'm sticking 3rd party until/unless they admit there is an issue and indicate how they are fixing it (higher rated PSU, or different supplier, or whatever).

Re: Power Supply failure

Another one bites the dust. 120V 45ish days printing time. Printer was preheating. Dark room saw a flash, printer lost power, fuse blown and a resistor looks like someone took a chisel to it.

Replacement on the way from Prusa.

At this time I don't feel like I should have to buy a 3rd party PSU.

Kinda irritated with the downtime as my printers have a backlog right now.

These PSUs are all failing in the exact same fashion. After my second PSU failed, I bought the MeanWell. I took the power panic module out of the 3rd one when it arrived. The MeanWell is a rock solid industrial quality PSU. The stock one is probably an $8 China special.

Re: Power Supply failure

My newly arrived MK3 is also clicking. Primarily when preheating, but occasionally even while printing.

I'm perfectly comfortable popping open the box and resoldering/replacing stuff if that's what is needed. Is that a fix? Or do I just wait for it to burst into flames?

Re: Power Supply failure

My newly arrived MK3 is also clicking. Primarily when preheating, but occasionally even while printing.

I'm perfectly comfortable popping open the box and resoldering/replacing stuff if that's what is needed. Is that a fix? Or do I just wait for it to burst into flames?

I've seen no indication that the clicking sound is related to the failure. It may be an indication of a PSU near it's limits, but no indication that the thing clicking is the thing that fails.

At this point, it's not at all clear what goes wrong with the PSUs. Different parts appear to be burnt out on different PSUs, and it may be that the actual failure is not even in those parts. It could be that something hidden causes an overcurrent situation and then the weakest part on your specific PSU is the one the burns up.

So: I would say keep your soldering iron for other stuff, and pick up a more solid PSU somewhere else. I wouldn't even wait for it to burst into flames.

Re: Power Supply failure

Just built mine today, mine is also clicking like crazy, pretty much always during prints. Working only with PLA at this point.

It perfectly lines up with the flashing of the bed power LED. I read something about a PWM setting, how does one go about changing that?

Hopefully my PSU doesn't fail, but I'm debating having a Meanwell in reserve anyway... How straightforward is removing/transplanting the power panic feature?

Re: Power Supply failure

I’ve had my Mk3 (pre-built) for two weeks now. Printed fine with PLA. I was printed PETG when there was a pop and a flash and the power died. The fuse is blown. I am in the US. I am waiting on a reply from Prusa.

So, add another power supply failure to the list.

Re: Power Supply failure

What is Prusa's take on this. To me it sounds like the PS is not adequate for 120v users.

I hear that this is just a small amount of failures compared to the number of units out there, but how many PS failures are not reported here?

Debra

Re: Power Supply failure

I have NOT had a power supply failure, but given this thread I got the Meanwell and finished installing it yesterday. I used this bracket: https://www.thingiverse.com/thing:2812350 . Be warned that it's a bit of a pain in the ass to do, and requires making new power leads out of 14 ga wire since the existing ones won't be long enough.