Power Supply failure  

Re: Power Supply failure

Add me to the long list of power supply failures.... it just happen whilst I was watching the last 5 mins of a 10h print. Little puff of smoke. 110v.

I guess I'm going to spend the morning with support... SIgh!

Did some more digging and think I found the fault. Resister R4 has blown. It's difficult to see in my picture taken through the vents, but it's exactly the same problem found by jltx in this post: https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/power-supply-failure-t13443-s90.html#p61363 . The resister has a crack through it and a brown smoke stain on the rear side. Like other experiences my fuse near the power connector did blow, but of course, replacing it didn't make a difference.

IMG_4285.jpg

I'm going to forward this on to Prusa support, but unless they have found a substitute power supply, I'm not sure I'm going to be able to trust it.

mine also same resistor, although mine split apart
https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/power-supply-failure-t13443-s140.html#p62776

Re: Power Supply failure

👿 👿

Add me to the list! I'm sooo sad! Almost two months with no problems. I was on with Prusa chat. He says the chat is very busy tonight. Lots of "try this" then waiting for him to return. Ended with him saying I needed to email info@prusa.

Why can't the chat support handle the return? He has all my details. At least get the process started. Now I have to wait for someone else to read my email and probably make me go through the same steps.

Re: Power Supply failure

I'm going to forward this on to Prusa support, but unless they have found a substitute power supply, I'm not sure I'm going to be able to trust it.

That's where I'm at. I had one fail, and the second they sent would drop to zero volts randomly when heating. I've got my 3rd prusa supply, but I'm using a meanwell. I assume that the prusa supply will blow eventually and I don't want it to take my Einsy or my house with it. Since I have the meanwell (to bridge the replacement gap, 2 day delivery vs a week for me from Prusa), I might as well use it as the more reliable supply.

Expecting the worst I purchased a Meanwell and waiting to build my MK3. I'll use the short up time to print a mounting bracket so that I can install it.

Re: Power Supply failure

Are there any long term experience with this Meanwell PSU on MK3? Many original MK3 PSUs are also running fine for couple month.

Re: Power Supply failure

Are there any long term experience with this Meanwell PSU on MK3? Many original MK3 PSUs are also running fine for couple month.

Received my MK3 in December. Been running it on a Meanwell since January. That's about as long term as you're going to get, since the printer didn't start shipping till end of November. I have been running various Meanwell PSUs for years however, and have never had one failure.

Re: Power Supply failure

👿 👿

Add me to the list! I'm sooo sad! Almost two months with no problems. I was on with Prusa chat. He says the chat is very busy tonight. Lots of "try this" then waiting for him to return. Ended with him saying I needed to email info@prusa.

Why can't the chat support handle the return? He has all my details. At least get the process started. Now I have to wait for someone else to read my email and probably make me go through the same steps.

Prusa was quick to respond to me and they initiated a replacement the next day. The problem is the time its going to take to get here. Despite the replacement I think I'm going to have to purchase a Meanwell for peace of mind. It's clear having now read this entire thread that it's not a question of if the PSU will fail, but rather when, at least for us on 110v system.

It's disappointing having spent a decent about of money on the printer, then having to print out a bunch of parts to fix belt issues, then having fan failures at slow speeds, then filament sensor false readings, and finally, when everything is printing well, I'm out of a week or two because of a PSU issue.

Re: Power Supply failure

Prusa was quick to respond to me and they initiated a replacement the next day. The problem is the time its going to take to get here. Despite the replacement I think I'm going to have to purchase a Meanwell for peace of mind. It's clear having now read this entire thread that it's not a question of if the PSU will fail, but rather when, at least for us on 110v system.

It's disappointing having spent a decent about of money on the printer, then having to print out a bunch of parts to fix belt issues, then having fan failures at slow speeds, then filament sensor false readings, and finally, when everything is printing well, I'm out of a week or two because of a PSU issue.

Is this the one I need?
https://www.amazon.com/Mean-NES-350-24-Switching-Power-Supply/dp/B00KTJE3L4/ref=sr_1_3?ie=UTF8&qid=1521901911&sr=8-3&keywords=meanwell+power+supply

Re: Power Supply failure

Prusa was quick to respond to me and they initiated a replacement the next day. The problem is the time its going to take to get here. Despite the replacement I think I'm going to have to purchase a Meanwell for peace of mind. It's clear having now read this entire thread that it's not a question of if the PSU will fail, but rather when, at least for us on 110v system.

It's disappointing having spent a decent about of money on the printer, then having to print out a bunch of parts to fix belt issues, then having fan failures at slow speeds, then filament sensor false readings, and finally, when everything is printing well, I'm out of a week or two because of a PSU issue.

Is this the one I need?
https://www.amazon.com/Mean-NES-350-24-Switching-Power-Supply/dp/B00KTJE3L4/ref=sr_1_3?ie=UTF8&qid=1521901911&sr=8-3&keywords=meanwell+power+supply

NVM I searched this thread and saw that this works as well as the LRS-350...which is $20 cheaper.

Re: Power Supply failure

Are there any long term experience with this Meanwell PSU on MK3? Many original MK3 PSUs are also running fine for couple month.

Received my MK3 in December. Been running it on a Meanwell since January. That's about as long term as you're going to get, since the printer didn't start shipping till end of November. I have been running various Meanwell PSUs for years however, and have never had one failure.

Is there any documentation that shows how the wires move from one PS to the other or is it self explanatory? Also, which mounting bracket did you use.

Re: Power Supply failure

Is there any documentation that shows how the wires move from one PS to the other or is it self explanatory? Also, which mounting bracket did you use.

I didn't use a bracket, I remote mounted my PSU. But do some more searching. Wiring and brackets have been discussed at length in this and other threads.

Re: Power Supply failure

Is this the one I need?
https://www.amazon.com/Mean-NES-350-24-Switching-Power-Supply/dp/B00KTJE3L4/ref=sr_1_3?ie=UTF8&qid=1521901911&sr=8-3&keywords=meanwell+power+supply

The NES model is discontinued (although still available in some places). The replacement is LRS-350-24 and is cheaper. I've heard the fan is noisy and at least one person has replaced the fan with a quieter one (search for "Gdstime Ultrathin 60mm x 60mm x 10mm" on Amazon).

A community member posted brackets here: https://makerware.thingiverse.com/thing:2812350

Re: Power Supply failure

I haven't received my printer yet, but i'm thinking about a replacement Meanwell PSU.
Does this Problem only appear at 110V? We have 230 V.
Some of you used the NES350-24 and some the LRS350-24. But what about SE 350-24 or the SP 320-24. What is different? Which would be best?

What material should be used for the bracket?

Thanks a lot.

Re: Power Supply failure

Prusa was quick to respond to me and they initiated a replacement the next day. The problem is the time its going to take to get here. Despite the replacement I think I'm going to have to purchase a Meanwell for peace of mind. It's clear having now read this entire thread that it's not a question of if the PSU will fail, but rather when, at least for us on 110v system.

It's disappointing having spent a decent about of money on the printer, then having to print out a bunch of parts to fix belt issues, then having fan failures at slow speeds, then filament sensor false readings, and finally, when everything is printing well, I'm out of a week or two because of a PSU issue.

Is this the one I need?
https://www.amazon.com/Mean-NES-350-24-Switching-Power-Supply/dp/B00KTJE3L4/ref=sr_1_3?ie=UTF8&qid=1521901911&sr=8-3&keywords=meanwell+power+supply

I think this is the same one and a lot less expensive. Don't know about shipping though. Remember the price is in CAD.

https://www.amazon.ca/Mean-Well-NES-350-24-Switching-Supply/dp/B00KTJE3L4/ref=sr_1_1?ie=UTF8&qid=1521908937&sr=8-1&keywords=Mean+Well+NES-350-24

Re: Power Supply failure

Hooked up the LRS-350-24 tonight and it works great! I'll print the enclosure that paul.m27 uploaded. Still dealing with Prusa support. They wanted pics of how it was attached to the einsy board 🙄 even though the thing ran fine for almost 2 months. I sent them that plus a video of the spark that comes out of the PSU when powered on.

So, did I void any warranty on the rest of the printer by hooking up an aftermarket power supply?

Re: Power Supply failure

I have to agree that the stock PSU being undersized is likely the cause of reliability issues. I have measured mine pulling 300W when warming up, so 350W should be plenty. The stock PSU is only rated 240W continuous with an unknown peak rating. A possible workaround is to start with a bed preheat so as to reduce the peak, but they really should just put in a proper sized PSU to begin with.

Not sure if related but I had to tighten the screw terminals on mine since they were on the loose side.

I wonder if the printers used in the factory have upgraded PSUs. Maybe they run practically 24/7 and therefore rarely go through a full warmup cycle.

Re: Power Supply failure

This may not be the right place for it but I just needed to get out a good old fashioned bitch. The Prusa is my second printer. I have an Anet A8 that I've been using for close to a year and it still kicks out reliable prints. It's loud, but that beast will print. I did my research. I wasn't sure if I was interested in 3d printing when I got it but I was fascinated. I knew when I went into buying it that in order for it to be safe and reliable that I would need to mod/improve it. I did that. Stiffened the frame, stabilized the Z axis, installed a mosfet, changed the Z axis adjusterment, installed a fused switchbox. Even some other minor things. However, I knew going into buying my $160.00 printer that I had a project on my hands.

I love 3d printing. I think it is amazing. So I decided get a second printer and upgrade. I thought I had done my research. Everyone gushed about the MK3. So I plunked down my money on a "better" more expensive printer. So far I've gotten 1 good print. I've had a bad thermistor and a bad psu. Admittedly, support has agreed to send me both parts free of charge. If that had happened on my Anet, I would have been SOL. It doesn't change the fact that I'm frustrated. So now I'm sitting with a very expensive paperweight while I wait for a new PSU. Meanwhile my "junk" Anet is printing non-stop. 75 days, 10 hours and 47 minutes of print time.

Re: Power Supply failure

I have to agree that the stock PSU being undersized is likely the cause of reliability issues. I have measured mine pulling 300W when warming up, so 350W should be plenty. The stock PSU is only rated 240W continuous with an unknown peak rating. A possible workaround is to start with a bed preheat so as to reduce the peak, but they really should just put in a proper sized PSU to begin with.

Not sure if related but I had to tighten the screw terminals on mine since they were on the loose side.

I wonder if the printers used in the factory have upgraded PSUs. Maybe they run practically 24/7 and therefore rarely go through a full warmup cycle.

If you measured anywhere near 300W, I assume you were measuring AC power on the mains side. The PSU's 240W rating refers to the wattage on the DC output, not the AC input. The highest wattage I have observed on the DC side during preheat is 245watts (which could show a measurement as high as ~295W on the AC side due to conversion loss).

That said, I totally agree the PSU is underpowered. Any device that regularly pulls 240-245 watts should not be shipping with a 240W PSU. Even a 300W PSU would provide an acceptable amount of headroom. I went a Meanwell 320W version myself.

Re: Power Supply failure

I have measured mine pulling 300W when warming up, so 350W should be plenty. The stock PSU is only rated 240W continuous with an unknown peak rating.

This explains alot! No wonder the PS's are popping off.

I wonder if the printers used in the factory have upgraded PSUs.

I don't think they have to. The PRUSA print farm is using 240v so "CORRECT ME IF I'M WRONG" their 240v system is basically using two 120v systems in parallel.
Does this provide them two times 240w for a total of 480?

Re: Power Supply failure

I have measured mine pulling 300W when warming up, so 350W should be plenty. The stock PSU is only rated 240W continuous with an unknown peak rating.

This explains alot! No wonder the PS's are popping off.

No, the printer is not pulling 300W DC from the PSU. That 300W was likely measured on the AC input side.

I wonder if the printers used in the factory have upgraded PSUs.

I don't think they have to. The PRUSA print farm is using 240v so "CORRECT ME IF I'M WRONG" their 240v system is basically using two 120v systems in parallel.
Does this provide them two times 240w for a total of 480?

No, that's not how that works. The PSU is auto-switching 110-240v. When used with 240V AC, the PSU simply draws 50% less amperage on the AC side of the circuit (and therefore some of the internal components are subjected to 50% less AC current, which might be one factor resulting in fewer failures on 240V). However the DC output side of the circuit should look virtually the same...still 24V DC and still maxxing out around 240W DC.

Re: Power Supply failure

To anyone wondering if they should take the plunge on the Meanwell upgrade.. it's really not very hard. If you undo all the wire ties you have plenty of room to install the new PSU without any need to run longer wires, it just fits in place. The 3D printed parts available fit great and everything works as it should.

The fan is crazy loud on the meanwell, the replacement fan people linked here is only marginally better. I tried just removing the fan entirely but the PSU gets a little too warm than I'd be comfortable with. I want to rig up a quieter fan somehow, maybe mounted on the outside of the PSU.