You don't need an HBA. I bought an ASM1166 SATA card with 6 ports, plus the 6 SATA ports on my motherboard, it works fine.
Thanks for confirming this! If I understand correctly, bandwidth will be limited if I use a multiplier, but that's not a huge issue when using something like Unraid where you're limited to single disk performance most of the time anyway, right?
Do you have any issues with your card? Some people complain about ports/disks disappearing and the card needing to be rebooted.
In the meantime, I wired up the power button, status LED and HDD activity LED. I didn't go through the roamer board, and just wired them directly using shortened dupont cables. Thanks for the headsup about the polarity! I double-checked my connection and everything is working now.
A TFX PSU will fit without much modification and be much quieter, I only had to dremel for the power connector. I'm using Arctic F8 PWM PST CO in mine, since I am not a professional at hacking up steel to fit 120mm fans, unlike @fl0w
I actually went ahead and installed an ATX power supply that I had laying around. It's rather big, but still fits fine with a regular ATX motherboard. I struggled to cut the metal because I'm not a pro either, and I don't have the correct tools..
Thanks for recommending the Arctic fans. I had already bought them after reading one of your previous posts
You can also install a blower fan in the area to the left of the motherboard, to blow air through a 1U CPU cooler like the Supermicro SNK-P0046P. Or some Noctua 40mm fans.
Good idea! Right now I'm using this low-profile CPU cooler: SilverStone SST-NT07-115X. It has a fan on top, so I'm hoping that'll be enough. I run a relatively light workload (Proxmox, Home Assistant, Unraid, and some containers). I already ran prime95 with the case open, and the CPU barely hit 60°C (underclocked CPU). Let's hope it'll be fine once everything is properly closed up.
Also 3D printed an IO Shield to hide the insides. If it restricts airflow too much, I can add some mesh to it.
All that's left now is powering up the backplane and closing everything up. I'm planning on soldering the original connectors to a regular Molex connector, and then connecting that to my PSU. I believe you did something similar? I saw some shrink wrap on one of your photos.