Mar 132022
 

So, following on from the fun and games of migrating a network, the other outcome of the flood is cleaning out hardware that wasn’t so lucky to escape the flood waters. My workplace does a lot of industrial automation and meter integration work, and the tool of choice lately has been Linux machines with NodeRED (this is what WideSky Edge is built on).

Seeing a chip-shortage, they bought up a big stock pile of these ruggedised Intel NUCs. These machines are no front-page news spec-wise (dual-core Intel Celeron, 4GB RAM, 64GB eMMC), but are good enough for the task. However, mother nature had other plans, and machines that were not IPX7 rated got a dunking no one anticipated. Miraculously, I’ve managed to get most of them going. Initially when I got them home was I gave them all a rise in tap water to just wash away any mud and other muck that may have been in the river water, then left them to dry for a few days.

This didn’t help matters, with units still refusing to power on, so I opened each one up and sprayed them with some isopropyl alcohol spray… using an entire 300g can of the stuff on 14 rugged NUCs. I did this to one at first… and found to my amazement, it booted!

She lives!!!

I did find though, there was no documentation on how to disassemble one of these. Intel’s docs don’t even tell you. And much of what I did find was YouTube videos… apparently people are incapable of taking still photos and documenting the process in plain text. Never mind, I figured it out, and will document the procedure here.

I’m not going to bother identifying chips, this isn’t iFixIt. I’m primarily concerned about cleaning off any muck that’s causing the boot failure.

Disassembly

So presumably you’ve got one of these NUCs in front of you.

The NUC8CCHKRN2

First step is to flip it over (front still facing you), and you’ll see 4 very obvious screws. These are captive screws, so no risk of them rattling loose.

The screws for opening the case.

Inside we see the WiFi/Bluetooth module, a space for a M.2 SSD/peripheral, the RTC battery and the top of the main board.

Inside the bottom cover

The first step I found easiest is to remove the screw and nut that holds the WiFi card in place. This is a spacer+screw assembly which does double-duty of holding the WiFi card down, and holding whatever full-length M.2 peripheral you put in there. Pliers work for rotating that nut. Removal will allow us to better get the coax antenna feeds out of the way to access the screw beneath.

The nut+screw assembly holding the WiFi card down

Now we have that out of the way, we can remove the screws that actually hold the inner chassis down. There are two screws, one on each side.

The screws holding the inner chassis frame in place

Now, to finally release the inner frame, there are two catches, one each side of the case.

The plastic catches holding the chassis frame in place

You’ll want to push the plastic outwards whilst pulling upward on the USB / Ethernet connectors. Do one side, pulling the frame out by 5mm, then do the other.

Catches away!

Having done this, you’ll see continuing to pull on these connectors, the whole assembly pulls out. From here, we now can focus on extracting the PCB from the inner chassis frame. The PCB is fixed by two screws which the silkscreen helpfully points out.

The inner chassis removed, two screws fix the PCB itself.

Undo these two screws, then flip the board over, you’ll find 4 more that bolt the heatsink to the CPU.

Heatsink screws

These screws are captive like the case screws in the initial step, so just undo each a few turns, move to the next screw and loosen it, etc, and keep going until the PCB comes loose.

…and we’re in!

The PCB should now come free and you’ll be able to see the CPU and RAM (which are soldered-on).