Power Supply failure  

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.

I too was very worried about the power supply clicking and I actually changed my order to an MK2S and then back to an MK3. I work for a company that manages laser printers and one of our printer techs told me that when you have devices that quickly pull a lot of voltage, like a laser printer heating a fusing unit, you can sometimes hear audible noises and clicks from the PSU as the power draws. A noise isn't an indication that there's a fault.

I think Prusa could save everyone a lot of stress if they can certify that the above case applies to this PSU. My printer very seldom clicks but when it does it's when the bed is drawing power to maintain temp after it's preheated.

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.

Hi Paul,

The frame adapter would be a solution for conversion. It should be easy to come up with something that holds the PS to the frame i.e. adapter mount bracket, clips etc,, It looks like the NES-350-24 has the same case dimensions as the SP-320-24 supply so maybe the plastic bottom AC box would work for either Meanwell model.

I plan on making this printer work for me as I feel it still offers what I want for the price....for now anyways!

Re: Power Supply failure

....I plan on making this printer work for me as I feel it still offers what I want for the price....for now anyways!

That's kind of my take, I'm too heavily invested to quit at this point. I kind of think that it will be a decent unit when all of the bugs are shaken out.

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.

I too was very worried about the power supply clicking and I actually changed my order to an MK2S and then back to an MK3. I work for a company that manages laser printers and one of our printer techs told me that when you have devices that quickly pull a lot of voltage, like a laser printer heating a fusing unit, you can sometimes hear audible noises and clicks from the PSU as the power draws. A noise isn't an indication that there's a fault.

I think Prusa could save everyone a lot of stress if they can certify that the above case applies to this PSU. My printer very seldom clicks but when it does it's when the bed is drawing power to maintain temp after it's preheated.

Yes. Electronics can be surprisingly noisy. I have supplies that hiss, squeal, pop... loudly. Can be very annoying but not necessarily a problem.

The ticking noise mine was making sounded like an electrical arc, like oven starter. So that was concerning but I don’t know that it’s a problem or if it’s related to the eventual failure. I suspect the noise is normal / unavoidable at this price point and my failure was a fluke.

I have a tracking number now for the replacement.

Re: Power Supply failure

Yes. Electronics can be surprisingly noisy. I have supplies that hiss, squeal, pop... loudly. Can be very annoying but not necessarily a problem.

The ticking noise mine was making sounded like an electrical arc, like oven starter. So that was concerning but I don’t know that it’s a problem or if it’s related to the eventual failure. I suspect the noise is normal / unavoidable at this price point and my failure was a fluke.

I have a tracking number now for the replacement.

My ticking sounds more like a tapping like if you were to tap your fingernail on the desk. It's not too noisy and if I step away from my printer I no longer hear it.

Re: Power Supply failure

Well I feel that the PS clicking is a result of another problem such as an under rated wattage power supply or a not so good quality of supply used. Regardless, I'll go along for the ride for now as long as the firmware side of the product gets refined to my satisfaction. I can always tweek the hardware and update the controller if needed. For my first printer however I didn't expect to have a list of upgrades ready to use when I build the kit.

🙄

Re: Power Supply failure

Only way I can think of software fixing this is sending lower power to the heating bed so the is less of a load on the power supply but that would also mean longer time for heating the bed.

I'm going to look into the 320w or 350w power supply my self, hope someone makes a new power supply base to fit those power supplies 😀

Re: Power Supply failure

Only way I can think of software fixing this is sending lower power to the heating bed so the is less of a load on the power supply but that would also mean longer time for heating the bed.

bugs...

I'm going to look into the 320w or 350w power supply my self, hope someone makes a new power supply base to fit those power supplies 😀

Except are you sure a few extra amps is going to solve something we don't even know is an issue. I went back and re-read this forum and I'm no expert on Power but everything seems to consist of the blind leading the blind. We have 4-5 PSU blown out of how many printers shipped? Were they running stock, no enclosure, modification etc. What was the environment (temp) the printer in like? Haven't seen any one post min/max loads on the existing power supplies capabilities, specs on power utilization of all components except some posts quoting other sources on power requirements that look to be based on 12v sources. Posts of replacement power supplies that look to perform about the same except for an active fan.

Not saying there isn't a potential issue, I'm sure Prusa is or has investigated beyond doing their development testing of power requirements. The biggest issue I see is Prusa letting this thread go so long without an official reply, some details on the ticking sound, power requirements etc.

Fixing something through assumptions or lack full understanding isn't always doesn't always make for a great fix.

Re: Power Supply failure

Only way I can think of software fixing this is sending lower power to the heating bed so the is less of a load on the power supply but that would also mean longer time for heating the bed.

bugs...

I'm going to look into the 320w or 350w power supply my self, hope someone makes a new power supply base to fit those power supplies 😀

Except are you sure a few extra amps is going to solve something we don't even know is an issue. I went back and re-read this forum and I'm no expert on Power but everything seems to consist of the blind leading the blind. We have 4-5 PSU blown out of how many printers shipped? Were they running stock, no enclosure, modification etc. What was the environment (temp) the printer in like? Haven't seen any one post min/max loads on the existing power supplies capabilities, specs on power utilization of all components except some posts quoting other sources on power requirements that look to be based on 12v sources. Posts of replacement power supplies that look to perform about the same except for an active fan.

Not saying there isn't a potential issue, I'm sure Prusa is or has investigated beyond doing their development testing of power requirements. The biggest issue I see is Prusa letting this thread go so long without an official reply, some details on the ticking sound, power requirements etc.

Fixing something through assumptions or lack full understanding isn't always doesn't always make for a great fix.

I think the biggest reason for the "blind leading the blind" you're seeing is that pretty much nothing at all has been said, and so those with ticking/noisy/dead PSU's have no choice but to go out and find something else that works.

And when I mean "no choice" I mean doing the kind of tinkering the hobby was built on 😉

Re: Power Supply failure

Or maybe it is like my situation when I build a new super silent desktop PC. Then I discovered that my old speakers makes silent but annoying noise and I had to buy the new ones. 🙂

Re: Power Supply failure

PSU section from the upcoming article reviewing last two months:-)

PSU sounds
Multiple things got mixed up together. We unfortunately made the printer too quiet, hh. First, there is the “rattling” which we found out to be the plastic insulation sheet between the PSU circuit board and its case. It is the same as on MK2/S but not as apparent over the sound of the motors. The sheet may resonate when the stepper motors hit its resonant frequency. There is not much we can do with it on the manufacturing side, insulation cannot be removed from the PSU. Some users remedied it with sliding a ziptie between the case and the sheet, but we discourage this. Little tweaking of travel speeds during calibration and switching Z motors into StealthChop will go a long way in one of the upcoming FW updates.
Some users reported PSU “clicking”. What happens is, when you switch to high load on the heated bed the input coil winding vibrate a little. It is physics. The fact this new PSU has active PFC may make this more pronounced, especially on 110V. But you can hear it with every PSU on both 120V and 230V when you stick your ear close enough. As we are preparing to integrate our whole PSU + PowerPanic + connector assembly into one unit - to reduce the assembly time, we have a power supply specialist in-house. So we could quickly find out that this is what is going on. They are perfectly safe and they were also tested when we were getting them tested for the CE marking at the external lab. The clicking can be reduced by increasing the PWM frequency for the heatbed in later FW, which we plan to implement.
During our manufacturing process every power supply gets tested twice. Once when it’s assembled. Under full load, we measure the voltage, amperage and milliseconds of power it has remaining in the caps for the PowerPanic feature. See our test jig below on the photo. The second time it is on our test station, where it again fully heats up the heated bed and hotend. Everyone gets a test protocol from this second test.
I am surprised with this level of scrutiny no one noticed the heatbed clicks too. As there are magnets embedded under the the heating traces, acting like a very weak speaker. Maybe we can eventually play MIDI files from the SD card one day. 😉

Re: Power Supply failure

Thank you, Josef, For the feedback. This should ease some minds out there.

Re: Power Supply failure

I'm going to look into the 320w or 350w power supply my self, hope someone makes a new power supply base to fit those power supplies 😀

Working on the Meanwell 350 now. I'll put it in scad format so people can tweak it for others.

Hoping by tomorrow night I'll have a first pass.

Re: Power Supply failure

Except are you sure a few extra amps is going to solve something we don't even know is an issue. I went back and re-read this forum and I'm no expert on Power but everything seems to consist of the blind leading the blind. We have 4-5 PSU blown out of how many printers shipped? Were they running stock, no enclosure, modification etc. What was the environment (temp) the printer in like? Haven't seen any one post min/max loads on the existing power supplies capabilities, specs on power utilization of all components except some posts quoting other sources on power requirements that look to be based on 12v sources. Posts of replacement power supplies that look to perform about the same except for an active fan.

Not saying there isn't a potential issue, I'm sure Prusa is or has investigated beyond doing their development testing of power requirements. The biggest issue I see is Prusa letting this thread go so long without an official reply, some details on the ticking sound, power requirements etc.

Fixing something through assumptions or lack full understanding isn't always doesn't always make for a great fix.

Completely agree, it's anecdotal at this point.

I'm buying a new PSU because I suspect it will take a week or more to get my new one from Prusa (they offered it this morning, I accepted, but I haven't heard anything yet), and I can always use another supply (I've got a bunch of 12V lying around, but no 24V, which left me dead in the water when it died.)

BTW, my conditions:

- totally stock MK3
- running the updated octoprint firmware from Josef (early version with disabled linear advance)
- Ambient temp 68F or so
- No enclosure
- PETG with bed 85, nozzle 235 (240?)
- Probably at least an hour, maybe 3, into a print
- printing from SD, nothing connected to the USB port
- conditioned power (the non-battery backup plugs of a CyberPower CP1500PFCLCD PFC Sinewave UPS)

My wife was home when it happened. No flickering lights, no clocks/microwave/computers reset. No weather in the area at the time, so no reason to suspect a surge that could have gotten through the surge protection.

I'd had the printer running for about a month, running lots of PETG with the same temps before. I'd even run the same print the night before (forgot some support, so had to redo it). The print was the base of the egg printer on thingiverse, pretty generic.

I'm not concerned about my printer, I just got a bum PSU and Prusa quickly offered to replace it. Can't ask for more than that.

BTW, I picked up a Meanwell 350 for a few reasons:
- it was available in 2 days so I could print this weekend
- the Meanwell has a fan that runs when it gets hot. Going higher capacity I hoped I could minimize the fan running
- Why not?

I didn't do it because I thought the original PSU was underspecced, nor because of the clicking.

Re: Power Supply failure

...
During our manufacturing process every power supply gets tested twice. Once when it’s assembled. Under full load, we measure the voltage, amperage and milliseconds of power it has remaining in the caps for the PowerPanic feature. See our test jig below on the photo. The second time it is on our test station, where it again fully heats up the heated bed and hotend. Everyone gets a test protocol from this second test.
...

I don't doubt mine went through this testing just fine, it performed like a champ for a month. There is no way your production test could have caught an individual PSU like mine, with a PSU failing after 100+ hours of printing.

No concerns on my end, I just want to get back to printing.

I am curious if the clicking is different/louder/softer on my new PSU, but the original one never bothered me. It was actually a positive, because I could tell without looking when the bed had hit temp!

Re: Power Supply failure

My replacement supply arrived and the printer is back up and running. The failed one goes back today.

My configuration for those interested:

- totally stock MK3
- running the stock firmware, versions rc1_b122, rc3_b138, and rc4_b143
- Ambient temp 19-20C / 66-68F
- No enclosure
- PLA with stock settings
- Ran fine for two weeks before failure
- printing from SD only

Jim

Re: Power Supply failure

PSU section from the upcoming article reviewing last two months:-)

PSU sounds
Multiple things got mixed up together. We unfortunately made the printer too quiet, hh. First, there is the “rattling” which we found out to be the plastic insulation sheet between the PSU circuit board and its case. It is the same as on MK2/S but not as apparent over the sound of the motors. The sheet may resonate when the stepper motors hit its resonant frequency. There is not much we can do with it on the manufacturing side, insulation cannot be removed from the PSU. Some users remedied it with sliding a ziptie between the case and the sheet, but we discourage this. Little tweaking of travel speeds during calibration and switching Z motors into StealthChop will go a long way in one of the upcoming FW updates.
Some users reported PSU “clicking”. What happens is, when you switch to high load on the heated bed the input coil winding vibrate a little. It is physics. The fact this new PSU has active PFC may make this more pronounced, especially on 110V. But you can hear it with every PSU on both 120V and 230V when you stick your ear close enough. As we are preparing to integrate our whole PSU + PowerPanic + connector assembly into one unit - to reduce the assembly time, we have a power supply specialist in-house. So we could quickly find out that this is what is going on. They are perfectly safe and they were also tested when we were getting them tested for the CE marking at the external lab. The clicking can be reduced by increasing the PWM frequency for the heatbed in later FW, which we plan to implement.
During our manufacturing process every power supply gets tested twice. Once when it’s assembled. Under full load, we measure the voltage, amperage and milliseconds of power it has remaining in the caps for the PowerPanic feature. See our test jig below on the photo. The second time it is on our test station, where it again fully heats up the heated bed and hotend. Everyone gets a test protocol from this second test.
I am surprised with this level of scrutiny no one noticed the heatbed clicks too. As there are magnets embedded under the the heating traces, acting like a very weak speaker. Maybe we can eventually play MIDI files from the SD card one day. 😉

Thanks for the info and confirmation. Exactly as I suspected. Mine was just unlucky. Waiting for replacement to arrive.

Re: Power Supply failure

One note on the meanwell 350 I got. It works great (just have it wired up directly to the harness).

However, it has a fan. It's a heat triggered fan, and about once every 30 seconds or so it fires up for 1-2 seconds. It's not that loud, but the contrast is annoying... I was hoping that since it was overpowered by 1.5x it would run cool enough to not trigger the fan.

I'm printing a case for it anyway (just because) while I wait for my replacement supply. I want to check a few things:

Then I'll probably switch back to the replacement stock supply and keep the 350 watt one for projects.

Re: Power Supply failure

Replace it with noctua fan. However, this will require open the PSU and thus void warranty, i guess (or not? - maybe it doesn't have warranty labels across screws or borders...)

Re: Power Supply failure

One note on the meanwell 350 I got. It works great (just have it wired up directly to the harness).

However, it has a fan. It's a heat triggered fan, and about once every 30 seconds or so it fires up for 1-2 seconds. It's not that loud, but the contrast is annoying... I was hoping that since it was overpowered by 1.5x it would run cool enough to not trigger the fan.

I'm printing a case for it anyway (just because) while I wait for my replacement supply. I want to check a few things:

Then I'll probably switch back to the replacement stock supply and keep the 350 watt one for projects.

Be aware that the supply is not necessarily overpowered for your application. You are only using 2 of 3 channels and depending how they deigned it, you could have *less* amps available per channel. (14/3 < 10/2). You would have to open it up and see what they did. I also wouldn't assume it runs cooler.