LZX Capsule Low Noise Eurorack Power Supply

Sharing Lars’s post from Facebook for those who might not be on there!

“We have made our +/-12V +/-1A EuroRack power supply available as an open hardware design. Gerbers and Diptrace source files are available below. Do absolutely anything you want with it (except please, please don’t design poorly routed derivative PCBs.)
Experienced DIY’ers are welcome to help commit resources or export products to the repository. The switcher module this design uses is a little pricy, but available OTS from Mouser/DigiKey in low quantities, so it is a good design for DIY. For those without lots of hand SMT experience, this would be an advanced level SMT build due to the QFN parts. But it is low parts count on the SMT side.
This may not be identical to what we offer in the future, but it’s a solid EuroRack power supply design and now you own it.”

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The Mainboard looks like a 4layer board, the Switcher a 2layer board.

I see the mainboard has 11x (16pin) power connectors, so it acts as a busboard too. neat!

Some visuals:


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Here are the two internal copper layers. JLC’s gerber viewer doesn’t show you these. :stuck_out_tongue:
+/-12V fills and GND plane respectively:

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My first time messing around with diptrace but it looks like the switcher pcb is just an add on to mount/attach the DKA30A-12 to the main board? Passive SMD stuff looks like 0603. The TPS7A voltage regulators look a little tricky to hand solder but maybe not?

Anyone thinking of doing a pcb run? :slight_smile:

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JLCPCB might have these in stock, so a SMD populated pcb run would be possible.
I have to check their list some more. The TPS7A would be 5v right?

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Interesting! Looks like the non-basic parts are
TPS7A3301RGWR
TPS7A4700RGWR (not sure what voltage you’re looking for - the specs indicate a range for input and output, and mouser has low stock on these)
MURATA BNX (not sure which one? I may have not exported the BOM with all the info)

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a BOM would be handy
(I don’t have Diptrace installed here)

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BNX016-01 is the part that should be used here.
https://www.mouser.com/ProductDetail/Murata-Electronics/BNX016-01?qs=wcegd7B9MGv5f1vSnNmbeg%3D%3D

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thanks @eyesnoface, updated the sheet

@reverselandfill here’s the BOM, Not sure if I can share a csv on the forum. Happy to email or share via google if you want.

edit: not sure part 15 is a missing value resistor or just an extra line. Can take a closer look possibly tomorrow.

# Name Manufacturer Quantity
1 GRM188R71H104KA93D Murata Electronics 22
2 GRM188R71H103JA01D Murata Electronics 1
3 GRM319R6YA106KA12D Murata Electronics 6
4 870025574001 Wurth Electronics 2
5 GRM188R61H105KAALD Murata Electronics 2
6 WP424IDT Kingbright 2
7 SS5P10 Vishay 1
8 EUROPWR16_HORIZ 11
9 644456-4 TE Connectivity 4
10 39-30-1041 Molex 2
11 PJ-002A CUI 1
12 87230-3 TE Connectivity 1
13 BNX016-01 Murata Electronics 1
14 RC0603FR-071M5L Yageo 1
15 Yageo 1
16 RC0603FR-071KL Yageo 2
17 RC0603FR-0710KL Yageo 1
18 RC0603FR-070RL Yageo 2
19 TESTPOINT 3
20 TPS7A3301RGWR Texas Instruments 1
21 TPS7A4700RGWR Texas Instruments 1
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So… I’m in the market for a new PSU soon, would probably need one per 1U row, who do I give my money to? :wink:

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Screen caps of schematics:
LZX Capsule Main PCB Schematic

If unreadable in Discourse full res image.

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Is the switcher separated in order to elevate it for heat dissipation?

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Is anyone (ideally in the US) building/selling versions of this LZX-spec power supply, either as kits or built? :electric_plug:

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I have a few spare LZX Capsule power boards built by me for $150/ea + shipping. All tested and visually compared against a Malekko Power V1.3 with Shapechanger’s Stencil output and all looks good to me. I’m based in Portland, OR. DM if you’re interested.

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how do you solder those QFN parts? in a oven?

Nope, haven’t investigated getting an oven yet. For these I used a hot air gun + PCB preheater + low temp ChipQuik + flux. This is the rework station I used on this run:

https://www.circuitspecialists.com/csi853bplus.html

You could probably get away with using a regular hot air tool without the preheater–just spend a bit more time on the soaking stage with the hot air tool.

I potentially have two more boards I could put together and do a short video on it. Once you get used to the rough reflow timing and how the chips look once they’ve dropped, it’s pretty easy. Soldering the through hole headers probably took me the most time.

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thank you for sharing the unit I’ve been meaning to ask you . I have been looking for a ”recommended” preheat plate lazily for a bit now. I feel like there are so Many rebranded and/or wtf options out there including ali or eBay it feels like a dice roll to get one.

This is certainly in my price window.
How do you like it for your work?

I think deep down somewhere I’m just waiting & looking for an excuse to get a whizoo. But So far have been fairing fine with a hot air iron and a needle tip iron. Definitely am itching to get into that world of oven baked goodness. I always seem to eat the face off of at least one or five leds with the hot air tool, the plastic is so particular.

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Yeah, there are a ton of options out there for hot air rework stations / ovens and by no means am I claiming this is the best unit for a given budget. Circuitspecialists happened to have a sale on when I picked it up which helped. I have no huge complaints about the build quality since you could pay significantly more for a similar feature set, it seems.

I’d like to get an oven when I can afford it as this board and pretty much any SMT board you have a stencil / paste for would go much quicker. Then the temptation would be to find a cheap pick n’ place. :stuck_out_tongue:

Not sure if you meant SMT LEDs or through hole but in the latter case, try some kapton tape–it is amazing how much heat shielding it can provide. If it’s SMT LEDs and they’re getting chewed up during reflow, you probably need more flux and a lower temperature. You can always cheat a little bit with ChipQuik low temp solder if you’re just not getting on with a particular part. Preheating the whole board before the ramp up stage with your hot air tool helps so much, especially if you are fighting against a continuous ground plane in a multilayer board.

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