This NUC is Dead

Computers can wear out given enough time. I just had an old NUC basically fall apart – on the very day it was being replaced by a new one. The timing is rather too good to be believed, but basically the machine stopped working just when we transitioned to a new NUC. The old one still booted… but running it was questionable due to its many concurrent failure modes.

This NUC is Old

It was a NUC5i7, that I bought back in late 2015 or early 2016, and it was the currently oldest PC in the house. It was well overdue for replacement, but availability of new NUCs to replace it had been rather sketchy since the pandemic hit. I finally managed to score a NUC12 Enthusiast to replace it. Just in the nick of time!

Fan Noise… and then None

The fan noise from the machine had got pretty bad recently, but we attributed that to it having to work harder to run more recent software and games. Using a blower to clean out the fans through the ventilation openings provided some relief, so I did not think more about it.

The other day my wife complained that the machine was stuttering badly, failing to run some games and being very unresponsive. The usual rebooting did not help, and I started to suspect that the disk was broken. A CHKDSK found nothing odd.

But then I looked into Windows Task Manager and spotted something odd. It was stuck running at 1GHz or less all the time:

I have seen this before, and usually switching Windows power settings to Performance mode fixes it. Not so this time.

It’s Getting Hot in Here

Rebooting into BIOS to check the power settings showed up something quite shocking that also explained the machine behavior:

Photo of the BIOS screen showing the fan and temperature.

Note the 0 rpm on the CPU fan! That means the fan has stopped working. Stopped cooling the machine. Causing the CPU temperature to rise to over 100 degrees C.  Not a happy situation for a  computer. The case was really hot, and the fan was definitely not moving. The small bump up to 6000 rpm was me spraying air into the fan duct to see if I could get it moving.

Dirty Old Fan

With some advice from YouTube I managed to open up the NUC to get to the fan. Not a pretty sight:

The top of the motherboard. The top block is the air duct for pulling air in and blowing it out.

Cleaning it had no effect. I have ordered a replacement fan, maybe I can do some surgery on it and revive it. Or maybe it has totally burned out.

During the disassembly process, I learnt that the old NUC case design is very elegant: the motherboard is just slotted into place in an aluminum case. The case also works decently as an emergency heatsink.

Tired Old Disk

Even without the fan failure, this NUC was overdue for replacement. In particular, its SSD was on its last legs. According to the Solidigm Storage Tool (that you have to use with old Intel-brand SSDs nowadays), it had less than 10% of its life left:

I suppose this also had some impact on the performance of the system, at least until the point where the fan broke. Having a rather full SSD at the end of its life in a system that is very warm is not a recipe for great performance.

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