Power Supply failure  

Re: Power Supply failure

Took my PR-assembled and calibrated unit out of the box, started an ABS print, immediately noticed the clicking noise...

Really trying hard to be reasonable about this, but it sure stings paying a grand for something and having such a foundational problem right out of the gate.

Re: Power Supply failure

In all my years with electronics I have never heard a good power supply make that kind of sound. Sounds like the gas stove electronic ignition.

Re: Power Supply failure

Just received my MK3 assembled today. Right out of the box I had no power. After trying different outlets thinking my APC was to blame, I moved the bed and it powered on. Strange. Firmware update and calibration test done, proceeded to print an example off the SD card. About 20 minutes into the print, the printer shut off again. After checking and unplug/replug, it powered on but didn't save the system state so the print was no good. Not looking great out of the box. Is this similar to what others are seeing? Random PSU shutdown?

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Forgot to add, the power supply is making this 'tick tick tick' noise every few seconds. Reminds me of my gas stove when you first turn it on for the pilot to light.

Re: Power Supply failure

My printer just died mid-print. Power available, but flipping the switch gives no response. I'm at work, so I can't debug until I get home. Just contacted Prusa support, and I'll start walking through to figure out the issue (PSU, fuse, blown board, whatever).

On the off chance it is a PSU issue, I'm looking to pick up a replacement/backup. I definitely don't want to be waiting for one shipped from Europe.

Has anyone seen the STL or SCAD file for the PSU holder? I don't see it on github. If there is a beefy PSU (400W+) that fits in the existing piece, that would be ideal. Alternatively, I'll use that stl/scad file as a starting point to design my own.

Re: Power Supply failure

My printer just died mid-print. Power available, but flipping the switch gives no response. I'm at work, so I can't debug until I get home. Just contacted Prusa support, and I'll start walking through to figure out the issue (PSU, fuse, blown board, whatever).

On the off chance it is a PSU issue, I'm looking to pick up a replacement/backup. I definitely don't want to be waiting for one shipped from Europe.

Has anyone seen the STL or SCAD file for the PSU holder? I don't see it on github. If there is a beefy PSU (400W+) that fits in the existing piece, that would be ideal. Alternatively, I'll use that stl/scad file as a starting point to design my own.

Sounds like my failure. I finally convinced Prusa that the PSU is dead so they are sending a replacement. FYI, there is a fuse above the plug socket, but that was not my problem.

In the meantime I ordered a replacement since I’ve already lost a week. I think it will fit the stock mount. Worst case I’ll lay it down next. PSU case does provide some frame reinforcement so factor that in.

Re: Power Supply failure

In the meantime I ordered a replacement since I’ve already lost a week. I think it will fit the stock mount. Worst case I’ll lay it down next. PSU case does provide some frame reinforcement so factor that in.

What PSU did you buy?

I bought this:

https://www.amazon.com/gp/product/B00KTJE3L4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Overspecced, but reviews say it is quiet, and I'm hoping a 14A supply will let it run cool/quiet and last a long time. Plus I can get it free shipping by Friday so I can print this weekend.

I suspect it won't fit the current base. To start, I'll just leave the current PSU in place as a structural component and have my new one lying on the table wired to the Einsy. Then I'll explore whether my new PSU has the side holes required to support the frame, or I'll have to drill/tap my new PSU.

Joy. Hopefully I'll get luck and it's just a fuse. Although that might even be worse, as it'll leave me wondering if it will happen again (since this was just a normal PETG print, about 3 hours in, 230 nozzle, 85 bed)

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Thanks, I threw one in my Amazon cart so I know what to get if I have an issue..

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Yikes.... Not the kind of stuff you want to hear. I'm in week 50, so i've got a while before mine ships. When you guys with dead PSU's have contacted Prusa, have they indicated that this is a known issue? Have there been any official comments made? I'd like to think it will be sorted out by [supposedly] Feb 20th and onward, but still... Not good. Thanks to all of you guys doing the digging and guinea pigging and stuff, makes us late order folk's lives a lot easier! 😆

Re: Power Supply failure

Here is one of the supplies I posted earlier in this thread among a few others at 240W.

SP-320-24 24v/312w
http://www.meanwellusa.com/webapp/product/search.aspx?prod=SP-320

https://www.alliedelec.com/mean-well-usa-sp-320-24/70069598/
New to 3D printing, Designed and built CNC Plasma Cutting Table, Motorcycle

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It seems to me that neither of the above linked power supplies will support the power panic feature.

Re: Power Supply failure

It seems to me that neither of the above linked power supplies will support the power panic feature.

I was concerned about that as well, but turns out it's not an issue. As part of debugging my current PSU fail, I disassembled the switch/plug/psu assembly. The black/white power-panic wires come from a small circuit board independent of the PSU that is connected directly to the mains power. The mains power goes to this board and independently it goes directly to the PSU.

I'm assuming the board simply monitors mains power (not the 24v PSU output, and with no communication with the PSU). If the mains power drops, it signals the Einsy. This probably buys them a few ms of power, as the PSU can probably keep supplying 24V for a short while after mains power is cut.

The bigger concern for me now is whether replacement PSUs will be drilled/tapped in the correct places to support the frame. I'll let you know Friday for my Mean Well 350 W version.

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It seems to me that neither of the above linked power supplies will support the power panic feature.

The Power Panic feature is implemented by a PR circuit board added into the power supply enclosure.

See https://github.com/prusa3d/MK3_Power_Panic

Though it may be possible to remove the Power Panic board from the original supply and install it onto another unit, I recommend extreme caution because you will be connecting mains voltages (120v/220v). Also, these other supplies may or may not have enough reserve capacitance to deliver 24v for several hundred milliseconds after mains is lost, to successfully execute the firmware PP save feature.

Edit: Sorry, Paul, it appears we were both typing replies simultaneously.

Re: Power Supply failure

I mentioned in my earlier posts about the possibility of these alternate supplies not being able to provide the output voltage hold up time as the original Prusa supply. I think the AC lines sense board just sits in the black plastic case where the AC switch is and should be easily reused. Or design a new lower plastic cover.

https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/power-supply-failure-t13443-s20.html#p59815

Go out to the Meanwell web site and look for the data sheet on that power supply you ordered and it will give you the case mechanical information.

Re: Power Supply failure

The Power Panic feature is implemented by a PR circuit board added into the power supply enclosure.

See https://github.com/prusa3d/MK3_Power_Panic

Though it may be possible to remove the Power Panic board from the original supply and install it onto another unit, I recommend extreme caution because you will be connecting mains voltages (120v/220v). Also, these other supplies may or may not have enough reserve capacitance to deliver 24v for several hundred milliseconds after mains is lost, to successfully execute the firmware PP save feature.

I'll let you know, as I'm likely going to do it this weekend. The mk3 PSU looks like a pretty generic 24v 10A PSU. I suspect they didn't buy a special one to get extra capacitance on the 24V out, so I'm pretty confident my new PSU will work as well. Not that I really care, in my five years of printing on an ultimaker and rostock I've never lost a print to a mains power glitch.

Right now I'm running on a UPS anyway. I don't really have it for my printers (if I had a print going it would drain the battery pretty quickly) it's more for the computer and raspberry pi's. I just have the printers plugged into it for clean power.

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My PSU is dead. Waiting for Prusa support to contact me when they get in tomorrow.

My debug:

There is a fuse just above the plug: 5A, 250V glass fuse. It's an integral part of the plug assembly. That fuse is blown. Black inside, open circuit on my fluke. Yay! Maybe its just a bad fuse!

However, I didn't want to risk any more damage to the rest of the electronics, so I pulled the PSU. The plug/switch/PSU disassembles pretty easily giving you access to the standard fork terminals screwed into the PSU (2 +24/gnd pairs, and Ground/Neutral/Hot for supply). I disconnected those and removed the PSU. (There is also a small circuit board in that assembly that delivers the power-panic signal, see my post above)

Put the PSU on my bench, wired it to Hot/Neutral/Gnd on spare power cord. Flipped the switch on/off: slight bzzt, slight smell of smoke/ozone the first time. No visible smoke or visible damage inside. No 12V. No further sound on turning on/off the power. I suspect most of the magic smoke escaped when the fuse blew in the first place during the print.

For the record: I was probably 2-3 hours into an 8 hour print, PETG, 85C bed, 230C nozzle. I successfully ran the same print the night before and was rerunning it. The print looked fine.

Next step, wire up another 24V supply and see if my Einsy is still alive. I've got a replacement 350w PSU coming on Friday so I can print this weekend.

I'll let you know what Prusa says.

Re: Power Supply failure

Ah, I didn't realize the Power Panic was done with a slick custom board at the power supply- genius! I too would say that given this, any decent 24V power supply will have no less reserve capacity than the stock one provided with the Prusa. They are all built using the same basic design.

Paul- did you replace the blown fuse before you did your bench tests?

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Paul, here’s what I found on closer look. My fuse was blown too.

Re: Power Supply failure

I like the Meanwell supplies because they include a full covered case with a controlled fan, power factor correction (PFC) for better efficiency performance, Agency compliance rated and over temp, current and voltage control. Generally accepted as a quality product. I and not sure that the
240w, 320w or the 350w supplies will be a direct fit for the original but the 240w would have the best chance. Do the research on the mechanical dimensions and mounting information with the links I posted earlier or go to the Meanwell web site.

If anyone redesigns the lower plastic case cover for one of these supplies then please place a post in the thread for the rest of us to use.

Hope they work because I will probably need one as well.

Re: Power Supply failure

Ah, I didn't realize the Power Panic was done with a slick custom board at the power supply- genius! I too would say that given this, any decent 24V power supply will have no less reserve capacity than the stock one provided with the Prusa. They are all built using the same basic design.

Paul- did you replace the blown fuse before you did your bench tests?

I did not need to. The fuse is in the plug assembly, which I had set aside. I wired hot/neutral/ground of an old 3 prong power cord directly into the PSU supply terminals. That went into a power strip. Flipped the power strip on, bzzt, ozone. Finished killing whatever component failed and took out the fuse in the first place.

On a positive note, my printer still works! I hooked it up to a bench supply and the einsy/steppers/heaters are all good. Self test still gives me “left/right fans swapped” after running both fans in the right order, but that is a known firmware issue. Display works, I can move xyze and heat bed and nozzle. Einsy was not damaged.

Off to get the mechanicals for my new PSU (350 meanwell) so I can jury rig an attachment for it. I’ll share any new design I create. I want to use the original plug/switch/panic in there.