Major breakthrough today!
I wanted to fix the following:
- Graphical artefacts
- Random (and not so random) sudden shutdowns
- Fan noise
# Problem 1 - Graphical artefacts
As my last post showed, the artefacts got gradually worse. I was convinced it had to be the wiring, since the artefacts would go away if I shook the machine. Therefore, I opened the machine and added a great amount of hot glue on all the open connectors, including the TMDS-DVI-mod (
just as you did, Insane Cultist) and all the other connections to insulate. After that, I added some layers of electrical tape. I then mounted it with velcro to the underside of the PSU.
When I tested it, the iMac gave me this:
I then tried to connect my MBP to the screen, and it wasn't able to show anything at all. Totally black. I then decided to unplug the 90 degree HDMI cable, and connect another one I had laying around that I know is of good quality.
And voilá, a
perfect artefact-free image.
The only "problem" is that the cable is 1,5m, and I do not have a shorter one. I decided I'd try to coil it up inside, and it was a really tight fit.
It has now run for several hours, and haven't had a slightest hint of artefacting
# Problem 2 - Sudden death
The random shutdowns had gradually become more severe. Especially when running games, it would simply shut off.
These were the patterns I noticed:
- It consistently shut off when playing the game Dreamfall or Tomb Raider (2013)
- Sometimes it would shut off at random with no load
- It didn't seem heat related. The hottest this machine have been is 80 degrees celcius (104 farhenheit) under heavy load. When browsing the web and watching videos, it's usually 40 degrees celcius. (175 fahrenheit).
- It has never shut down during a benchmark, and I have seen the CPU hitting the wattage limit on HWMonitor (45w?) several times, and it has not shut down.
To further test whether it is hardware related or software related, I installed Ubuntu on a USB stick. It stayed on all the time, even when playing Dreamfall and Tomb Raider. I also tried to put the NUC into "Low power mode", but nothing changed. To remedy it, I played around with the SMBIOS settings, but nothing helped.
Despite my tests, I still had a bad feeling about the internal PSU, and as
Rehabman pointed out, it does sound sketchy running everything on the poor internal 190w PSU. Therefore, I decided to throw out the 19v upconverter, and install the original 120w power brick that came with the NUC.
To make it fit, I removed the DVD-cage completely. The power chord is wired into the original cables, after the clip. I did this to be able to seperate the bottom and the cage in future upgrades.
It was a major success! I have thrown a lot of challenges at it (benchmarks, games and so on), but it has not died on me yet. An unexpected bonus was that the "bird tweeting" produced by the machine stopped. I thought it came from the inverter, but obviously it must have come from the PSU. The "hard drive ticking noises" that I have complained about are also gone.
# Problem 3 - Fan noise
My first impression of the fan was that it wasn't that loud. But after using the machine for some weeks, I realized that it was actually quite noisy. It had a high pitched noise relative to the fan rpm.
To remedy it, I simply took it out of the cage, pulled of the sticker and the rubber seal, and applied generous amounts of sewing machine oil.
Then I spun the fan to spread the oil, and resealed it. I used some extra tape just in case, since the fan is mounted upside down. I don't want oil dripping down on my NUC. If you are planning to this,
do not use WD-40. It will have the opposite effect after a short while.
Now the fan noise is a lot better! There are probably fans that are even quieter than this, but this is more than good enough for me
So, to conclude, it has been a very productive day (though my wife doesn't agree)