GMKtec G3 SFF SATA Lid

Items in the pictures:

• GMKtec NucBox G3
• IOCREST M.2 PCIe3.0 to 8 Ports SATA 6G Multiplier Controller Card B/M key
• Mini SAS SFF-8087 right angle to 4 SATA 7P 180 degree
• ICY DOCK ToughArmor MB998SP-B 8 Bay 2.5" SATA Cage
• FSP Flex ATX 300W 80 Plus Gold Power Supply
• Heatsink Kit + 3M8810 Thermal Conductive Adhesive Tape (9mmx9mmx12mm)

Problem Statement

While the M.2 SATA adapter works fine with the G3, and all 8 disks show up on TrueNAS with proper serial numbers, the connectors protrude too much for the original lid to be used. An even bigger problem is with the M.2 adapter: it's flimsy and the form factor is not designed for the forces used when plugging in and unplugging the SFF-8087 cables. The instructions that came with the M.2 adapter state that you should remove the adapter from the PC before attempting to plug or unplug any cable. This works fine if you don't mind running the mini PC without a lid.

Design Points

There are two components to this project: the lid itself and the support block.

The support block bears any weight imparted on the M.2 adapter when plugging in the SFF cables. It has cutouts for the through-hole pins on the M.2, as well as for the bank of capacitors under the SFF connector. All forces are borne by the M.2 PCB only. The through-hole cutouts are narrow enough to allow the support block to lightly grip the M.2, enabling you to press it on and have it stay in place as you install the board onto the mini PC. They also help to keep the block in place after installation.

The lid is deliberately kept thick for strength, except for the area above the heatsinks I've installed on the M.2 adapter. It also features ventilation holes for convective heat dissipation, with air flowing in from the G3 case vents along the sides. Additionally, I've engraved the SATA slot/port numbers so you don't have to remember which connector corresponds to which SATA devices. Lastly, there are three pillars on the lid: the center one provides support (resting on the SATA M.2 screw post), and the two thinner ones secure the M.2 adapter in place when you unplug the SFF cables. The square holes on the lid are tight enough to prevent the SFF connectors from moving if you accidentally bump the cable connectors in any direction. Together with the support block, the M.2 adapter no longer flexes when you plug or unplug the SFF cables.