====== Refurbishing NUCs ======
NUCs are well-engineered systems and can find a useful second life. They are simple to maintain and upgrade. Their greatest weakness is their poor graphics capabilities.

===== Inventory =====
Many used items come as bare bones or missing parts, especially AC adapters and WiFi cards.

Examine for:
  * the model of the NUC and specifications
  * RAM (type and amount)
  * Storage (type, format, and amount)
  * is the power adapter included
  * condition (scratches, dust)

===== Cleaning =====
A thorough cleaning inside and out can restore even a very dusty NUC. Removing the NUC motherboard allows for a full clean. Canned air or a blower will help clean the CPU heat sink and fan. Cleaning gel does an excellent job restoring the device.

**NOTE** A very dirty CPU fan and device can indicate damage to the CPU cooling fan

===== Update BIOS =====
Be sure the BIOS is from 2019 or later to ensure you are not vulnerable to a critical security vulnerability. Windows update can update the BIOS in some cases.

===== CMOS Battery Check =====
A CR2032 3 volt lithium battery has about 3.3V new. They last around 5-7 years. When the voltage drops to 2.8-2.7V it is considered dead. Symptoms of a failing battery are error messages at boot time.

Intel NUCs have the date of manufacture on the bottom place, so it is easy to check the age of the CMOS battery, essentially a CR2032 wrapped in plastic, connected to a small electrical connector.

It is challenging to test the voltage with a multimeter, requiring removing the motherboard and using some very fine probes with your multimeter.

Some sources say to download and live boot the latest Ubuntu distribution and run "sensors". This should give you the current voltage read from the battery. However in my testing, the CMOS battery voltage is not included. Therefore my best recommendation is to ''cat /proc/driver/rtc'' which will give you a "batt_status : okay" at least.

===== Upgrades and Replacements =====
Some NUCs have built-in 32GB storage, enough to barely run Windows 10 these days. The "tall" NUCs have room for 2.5" drives. Many have space for mSATA SSD and others for a m.2 SSD.

Replacing any HDD with a faster SSD is highly recommended. The built-in 32GB storage is also relatively slow compared to 2.5" SATA III SSD. A __60GB or greater SSD__ is recommended.

As for RAM, read the Intel specifications for the type and maximum sizes of RAM SO-DIMM modules. Some devices only have one (1) RAM slot.

For older and slower NUCs, 8GB is sufficient for normal Windows 10 use. For higher performance applications, 16GB is recommended.

Many NUCs have a slot for a wireless card and come with antennas installed inside the case. For these, I recommend installing a wireless/Bluetooth card as it makes the device much more flexible.

A few NUCs do not have an ethernet LAN port at all. In these cases, a wireless card is extremely important. Otherwise an ethernet to USB adapter is required.

===== OS =====
If you are looking to build a Home Theater PC (HTPC), you can install OpenELEC or other operating system.

For a normal workstation, I prefer to build a Windows 10 system. Windows 8.1 and Windows 7 can be upgraded using the [[https://support.microsoft.com/en-us/topic/windows-10-update-assistant-3550dfb2-a015-7765-12ea-fba2ac36fb3f|Windows 10 Update Assistant]]. When a NUC arrives with Windows 10 Pro, it's more valuable than a Windows 10 Home edition.

NOTE If the NUC originally came with Windows, the OEM key in the BIOS will activate the installation, so give it a try. This key can be read using the Windows OEM Product Key Tool.

With limited RAM 2GB, [[https://www.linuxmint.com/|Linux Mint]] or [[https://zorinos.com/|Zorin OS]] are excellent choices for a basic desktop system.

When giving away a Windows NUC, I usually do a full reset and leave it at the initial Windows configuration screen. Pressing F-10 from this screen opens and command prompt, allowing running the ''shutdown /s /t0'' command.

For a Linux NUC, I generally do a full re-install and set it to login automatically. I leave the credentials in a text note on the "desktop".

NOTE [[https://www.microsoft.com/en-us/windows/windows-11-specifications|Windows 11 requirements]] are greater:
  * Processor with 2 or more cores
  * Graphics: Compatible with DirectX 12 or later with WDDM 2.0 driver
  * 64 GB or larger storage device
  * 4GB RAM
  * TPM v.2.0
  * Windows 11 Home edition requires internet connectivity and a Microsoft account to complete device setup on first use
  * Display: High definition (720p) display that is greater than 9” diagonally, 8 bits per color channel