Reddit reviews MEAN WELL LRS-350-24 350.4W 24V 14.6 Amp Single Output Switchable Power

I assume you are talking about the fan in the PSU since that is what the picture is of... It is thermally controlled and only comes on if the PSU warms up and needs to be cooled... it doesn't run all the time....

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If your isn't coming on ever it may be bad or the connection loose...

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proceed at your own risk -

unplug from the wall... turn the power switch on to drain off any residual power... disconnect the PSU (take pictures and label the wires BEFORE you disconnect everything so you can reconnect it all... There should be 2~4 screws that hold the top case cover on the PSU... remove them and just the top with the fan attached will come loose... You don't need to take it any farther apart and so long as you don't go poking around all the hazardous bits should be discharged or not exposed...

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Check that the wire is plugged into the board before you pull it all the way off... if it isn't plugged in that is your problem... if it was plugged in you can order a new fan on Amazon or wherever for not much $$... in my case the fan is a 50mm square by 10mm tall and 24vdc .... .. yours may be different.... so measure it before you order....

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In an ideal world you want to order a fan that has double ball bearings or needle bearings... they will last longer and move more air for less power... The typical type fans included on the cheaper 3d printer have a sleeve bearing... those are OK in a very specific use case ---- horizontal mount and not subject to movement or shocks... so if your PSU is mounted vertically on the rail it will work, but isn't the ideal bearing type... Just order the double ball bearing type and you won't need to replace it again... pay attention to the picture and get a fan with the correct power connector on it already... otherwise you may have to splice the wires from the old fan onto the new one...

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IF you aren't comfortable taking apart the PSU here is a link that would be a good upgrade/replacement to your stock PSU

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https://smile.amazon.com/gp/product/B013ETVO12

I am on my third psu now. Yes, that is the correct fuse and it supposed to be slow blow. It's an exact replacement.

Bad news is, I'm almost certain It's not just the fuse that is blown. The mk3's psu's are well known to fail, and while some people say that there are just bad apples, I think the psu can't handle the higher draw when printing higher temp materials. If you were to open up your psu, I'm almost certain you would find the permanent on board fuse soldered to the board to be blown as well, and possibly also one of the components busted and burnt where it failed. Prusa will replace the psu under warranty, but in my case it just happened a second time. Same thing.

So here is what I would do if I were you. Go on Amazon and buy this. Not only is this psu way more reliable than the cheap Chinese one prusa ships with, it is capable of much more and will not fail you. Well worth the 30 bucks. This is the mount you will need to print to attach it to the printer. This fits perfectly, and uses mostly the screws and nuts from the stock psu except for one kind of screw you need 5 of. I made the upgrade and it is so much better than the stock psu. It has a fan that makes the printer slightly louder and it runs intermittently, but it also gets rid of the ticking from the heated bet and makes everything run a bit smoother. You can either hook up the replacement prusa sends you temporarily in order to print the mount, or you can do what I did and hook the meanwell up next to the printer to print the mount then mount it properly. Just be careful if you do as there will be exposed terminals that could shock you.

There is a great write up on the prusa forum detailing exactly how to do this and everything you need

MEAN WELL LRS-350-24 350.4W 24V 14.6 Amp Single Output Switchable Power https://www.amazon.com/dp/B013ETVO12/ref=cm_sw_r_cp_apa_i_LEJMDbBSKZVQE

This model will work fine.

> Mean Well LRS 350-24 power supply

This one? https://www.amazon.com/dp/B013ETVO12/

If you use 15 volts the max output is 15 watts per channel into 8 Ohms. You get 30 watts with a 24 volt supply.

The chips will need heatsinks if your load is more than 15 watts per channel.

https://www.amazon.com/MEAN-WELL-LRS-350-24-350-4W-Switchable/dp/B013ETVO12/

The output quality will be fairly low so I recommend some filtering before the amps in order to smooth out voltage ripple.

Check this one out on Amazon. It's a meanwell as previously posted but slimmer. I bought this myself when my power source died recently. It has been perfect so far and is thinner than the factory one. I liked this but had to reprint the mount and lengthen the wires going to the board. Worth it in the end.
MEAN WELL LRS-350-24 350.4W 24V 14.6 Amp Single Output Switchable Power https://www.amazon.com/dp/B013ETVO12/ref=cm_sw_r_cp_apa_RmR2AbG1XW1EY

Meanwell power supply:

https://www.amazon.com/gp/product/B013ETVO12

Ferrules and crimper:

https://www.amazon.com/gp/product/B07LCF39W9

Stepper smoothers (3-pack):

https://www.amazon.com/gp/product/B0727QT316

Capricorn PTFE tubing:

https://www.amazon.com/gp/product/B079P92HN9

Performance 3-D MK8 Apollo 0.4mm extruder nozzle:

https://www.p3-d.com/collections/duraplat-3d-extruder-nozzles

Glass bed (appears to be produced by creality), ebay seller usbkits :

https://www.ebay.com/itm/Creality-3D-Ender3-Ultrabase-Heat-Bed-Glass-Plate-235x235mm-for-3D-Printer-X6W6/143049426638

Aluminum drive feed, ebay seller creality-3d-direct :

https://www.ebay.com/itm/Upgrade-Aluminum-Extruder-Drive-Feed-Frame-For-Creality-Ender-3-3D-Printer/223095519332

***the tube fitting in this kit did not work well, so I used the fitting from the stock creality assembly and it worked fine.

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THD Firmware:

https://www.th3dstudio.com/knowledgebase/th3d-unified-firmware-package/

I bought this one: https://smile.amazon.com/gp/product/B013ETVO12/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Unfortunately, as soon as I powered it on, the RFI was back. No change. I'll keep the PSU since it's supposed to be better quality than the original, but it is thinner than the original and needs a different box. I tried printing one from TH3D but it was slightly too narrow and it cracked when I tried to put it on. Oh well.

So if the PSU isn't the culprit, my next guess was the fans. So I opened the electronics bay and disconnected them. No change.

So, either it's the board itself (1.1.5 silent), or the steppers?

Has anyone else seen RFI?

I bought a Mean Well from Amazon
https://www.amazon.com/gp/product/B013ETVO12/ref=ppx_yo_dt_b_asin_image_o02_s00?ie=UTF8&psc=1

I have the following items for sale:

Timestamps

Item | Price | Description
---------|----------|----------
Samsung Dex Pad | $93 Shipped | Brand new and still sealed
MEAN WELL LRS-350-24 350.4W 24V 14.6A PSU | $32 Shipped | Brand new and still sealed
CORSAIR M65 Pro RGB | $46 Shipped | Brand new and still sealed
P3 P4400 Kill A Watt Electricity Usage Monitor| $18 Shipped | Brand new. Just Tested before buying a smart switch.
Lenovo Ideapad 500s | $460 Shipped | Use this laptop only for app development. I haven't used it for months now. No scratch or anything. Comes with only charger and a wireless mouse.
Caselabs Mercury S8 Mounting Plate, Black, New | $9 shipped | NA.
Caselabs Mercury Flex-Bay Cover, Double Ventilated, New | $9.5 shipped |
Bitspower Dual / Single D5 Top Upgrade Kit 150 (Black POM Cap) | $32 shipped | Brand new, unused. It includes BP-WTZPC1-BK x 1PCS, BP-WTZACT150-CL x 1PCS, BP-DSRAP-BK x 1PCS and BP-DSBRA-MBK x 1Set.
Bitspower Mod Kit Support Bracket | $13 | Brand new.

Please reply to post before sending a PM. Local pick up is available at Buffalo Grove, 60089. Let me know if you have any questions. Moreover, prices are negotiable. Thanks for looking.

you could use something like this for cheap.

https://www.amazon.com/MEAN-WELL-LRS-350-24-350-4W-Switchable/dp/B013ETVO12

MEAN WELL LRS-350-24 350.4W 24V

https://www.amazon.com/dp/B013ETVO12


This is the common replacement that people are using. There's some blog posts out there about the issue, as well as printed parts for this PSU.

If you're super concerned, it's a cheap upgrade.

I understand, sorry hard to stand in your shoes and tell you what to do. Depends if you want to take the risk. You could attempt to at least get the difference of $20 back, because they sent you the cheaper option (and you can prove that with pictures)

Worst case, I see the power supply is around $30 on Amazon.com, not too bad

The pro has a different bed surface, a neat magnetic one they sell by itself for around 18$ on amazon, an upgraded power supply that runs around 30$ on amazon, and a beefier Y axis bar. 40x40 instead of 20x40. The electronics area is inverted making a small fan cover print not needed. This is about all there is different from the regular ender 3.

Considering the two interesting parts are under 50$, I don't think it's worth going for the pro vs just getting those two parts yourself and upgrading.

Neither the ender 3 nor the pro have a bootloader, so be sure to add a tinyisp programmer to your aliexpress order.

My silver PSU on my MK3 just died during a PETG print this week. Hoping Prusa will send me a new one, but from digging around all morning yesterday, it seems this PSU on Amazon is a good replacement with a little bit more power. This is my backup plan if my printer is not under warranty anymore.

PSU:
MEAN WELL LRS-350-24 350.4W 24V 14.6 Amp Single Output Switchable Power
https://www.amazon.com/dp/B013ETVO12/ref=cm_sw_r_cp_tai_DgnGDbHE4NVDW

PSU holder on Thingiverse:
https://www.thingiverse.com/thing:2812350