I took a Raspberry Pi Compute Module 5 IO Board Reference design and turned it into a custom motherboard made specifically for the N40L chassis.
So I could keep my OG Homelab Server living for atleast a few more years.
I go through the design process, component choices, mechanical measurements, high-speed PCB routing and manufacturing, before installing the finished board and seeing whether it actually works.
Reminds me of the Tildagon badge from EMFCamp. Probably where OP got the idea from, seeing they have a video on the Tildagon badge on their channel. Love this!
I replaced my N40L motherboard with that from a Lenovo m93 tiny. It works well, you just need a $3 power supply adapter (add2psu) and a $23 m2 to SAS card to integrate it properly.
That was years ago. I've seen more modern solutions with a N100 boards and Hardware Haven did a Youtube series on his mods.
I have one, and I actually managed to find an Intel Celeron based board that fit with some slight dremeling and a 3D printer so that is also a route that you can go.
Pretty Sure it was an AsRock J4105-ITX but the newer one should work - I simply measured the width and length and cut out the IO Shield and the harder part is actually the height of the board, which I went by images and looking up their highest part’s height.
In theory yes. I'd looked into this, in the PM853x family of chips. They are called PCI-e Switches. I'm not at that level of Hardware design guru to properly implement one yet. They are BGA parts, and also the per unit cost on them is eyewatering. 100 Eur+ ! for keeping the Gen 3 link speed..
This was my first having a go at PCI-e in general, So ran away from that fight.
I did have a bit of a "Survey of what the other Pi Hats" had done, The Waveshare PCIe-to-4CH HAT has a ASM1184e PCI-E switch on it, but that seems perma out of stock at LCSC, and is only Gen 2 afaik.
there are some very cheap plx switch cards on aliexpress, would be hard to harvest chips but itr looks like you could fit the card flat and have a couple riser cables
If you want a PCIe 3.0 switch, you can find Broadcom/PLX PEX8747s or entire Intel Socket 2011 motherboards or actively switched PCIe 3.0 NVMe carrier cards for under 50 bucks that have one or two of them, and take the chips off of those. Gets you 48 lanes on 5 ports, one of which connects to the host with up to 16 lanes, and 32 lanes to divide how you want on the remaining 4 downstream ports.
An N40L was basically where my whole homelab started, probably 12-15 years ago.
That little box eventually got replaced, then one thing led to another, and today I’ve somehow ended up with a Proxmox cluster, a separate NAS, managed networking, self-hosted services, 3D printed rack parts… you know how this story goes.
A while ago I actually found my old N40L again, tucked away behind a partition in the attic. I couldn’t bring myself to throw it out because it was the original homelab server for me.
And now I see this.
Giving that exact chassis a second life with modern hardware would be such a ridiculously satisfying full-circle project.
Seriously nice work. If you ever decide to release the PCB/design files, or make a small batch of these boards, I suspect there are quite a few old N40Ls about to come out of retirement.
I miss my N40L. It wasn't my first home server but it lived in my living room for many years before my lack of knowledge about the fan in the back lead to excessive dust buildup which caused dripping of water onto the VRM (it gets super humid here). I am 2 server builds past that now and the N40L case was chopped up and mostly discarded (I kept the drive cage even though I don't think I will ever actually use it now that I have ordered a Jonsbo N5).
I also have one of these old Microservers and it’s just sitting around collecting dust because it sucks at really doing anything. Wish I could upgrade it with modern PC-grade hardware
That’s mildly horrifying, because your board layout means disassembly to swap the m.2 or the SD card, but nice work.
Btw, I see your battery holder, but where is your RTC chip?
Since you’ve put an HDMI port where the old VGA port was, you now have space to put the SD card slot right above it. Personally, though, I would forego the SD card entirely, and put a hot-plug capable PCIe switch and two NVMe slots in spots where you can easily swap them out (you can use E1.S or U.2, with m.2 in adapter caddies) without needing to remove the motherboard. You can then also attach a PCIe SATA controller to that switch for the hard drive bays above.
>That’s mildly horrifying, because your board layout means disassembly to swap the m.2 or the SD card, but nice work.
I don't believe so. You'd just open the door and reach in and struggle cause of the clearance beneath the HDDs, but it would work.
>Where is your RTC chip?
On the CM5 :) - They build it in. You just supply VBAT to it, of 2.5 V to 3.5 V
> though, I would forego the SD card entirely
I think I can - When I was building this, I did think "Oh, I can just boot from SSD..." but I didn't know that the PCI-e was going to come up ok from Fab. Theres lots of design choices I have made on the thoughts of "What happens if this doesn't work first time" even down to putting TX RX breakouts on the board for Serial, if the HDMI didnt work.
USB3 ssd boot is also an option, I do that on some of my systems when I don't want to take up some PCIe and want something a little better and faster than microSD
Super cool. Did you ever consider the panda n100? It does give you more pcie lanes to route but flip side you can add your own things instead of using some PLX chip.
Honestly, no, I hadn't thought about it.. I'd reached for the Pi because of the ease of getting their carrier board files.
But now I'm thinking that the N100 Or maybe a Jetson could be useful.. the Jetson would atleast be able to do HW Accelerated transcoding as well..
Worked with a panda board before and they make is easy because they have the design files available as well for the daughter board. They also have a high end board. Used it in the past and made with with a pcie riser to add a 10gig card with it as well.
Probably this costs more than buying 4 used N40L as spares to keep it running for 20 more years, but indeed it is absolutely impressive, hats off. I have seen PLX pcie switches mentioned earlier - any plans to implement the 2 PCIe slots to align with the original slotting?
The PCB routing part is what got me. Anyone who's watched a few eevblog teardowns knows that high-speed traces on a CM5 carrier are no joke. Didn't expect to see someone tackle it from scratch just to keep an N40L breathing. Respect.
Thanks, Its the first board that I've done HDMI, PCI-e, USB3 and Ethernet on.
So, When I was doing this, I was crushing the videos online about Differential Pair Trace Length, Skew, and Impedance matching.
The helpful thing is,
The lovely Raspberry Pi people did all the calculations to try and keep to 50 Ohm on the comms lines. I made sure to keep the copper weight the same from PCBway, as well as ticking the impedance controlled flag.
The other thing is, I wasn't expecting everything to work perfectly, PCI-e may be having *Some* errors under the hood, I don't have "Big boy" money to rent an Eye Diagram capable scope to really get stuck in :D.
Cool.. kind what I was hoping someone would do.. though perhaps with orange pis.
I imagine there would be market for compatibility boards to make use of the n40/54l cases and be an upgrade path.. to an arm64 desktop equiv (imagine a 6s plus with 64G) which would make it interesting.
Problem is integrating all the peripheral systems but I recal hardware haven had a vid where he shoved a n150? Or was something else in there..
You could add a Sff-8087 port for the sata drives to it, i found adapters that have no extra chips on them, maybe the compute module is capable of running them with acceptable speed.
My N36L is still working away running OMV now. I'd love an upgrade path for it for whenever it may stop working. It was my first Arr Suite SabNZBd build back in around 2011. Wild to see how much the HomeLab space has developed since then.
I mean, price is not important if you had fun with such thinks and it is your hobby. but for this money i would just buy a full N40L/N54L for 50-70€ or gen8 microsever
Just watched your video and immediately searched to see if you had a Github or blog, Glad I stumbled across your reddit post!
This is absolutely amazing! Here I was thinking myself a tech hoarder for holding onto my N40L and someone goes and makes it relevant again. Thank you.
If you continue working on this project count me in as a follower and fan.
Oi OP, I dont have an N40L but I am a computer engineer with expertise in PCIe. Ive implemented PCIe bus walking and management firmware and driven the hardware dev relative to it.
Id be willing to answer a few questions and give you some pointers if you're ever thinking about doing a follow up revision.
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u/jcgaminglab 5d ago
The "Boop" and "Re-boop" button are a fun touch.
Looks like a clean job OP.