Here's my report: I did a 6 TB drive upgrade today, and re-lubricated the fan. The old unit was getting noisy and overheated due to accumulated dust. Lots of tiny clips and connectors to detach, but it is quite easy to re-open, once you've done it once. Just don't pull from the wires, there's a correct way to remove everything without force.
The unit now works quietly again, with much more space. I used a WD 6T Red drive, as it was readily available off the shelf in the local store and was reasonably priced.
There was some damage though, some of it semi-intentional. It's an old unit and it's my own, and I didn't really care about keeping it pristine, as long as it does its One Job: backups.
- The status LED assembly was so flimsy and useless that I just ripped it off and threw away. Won't miss it.
- Turns out the Reset button "connector" actually isn't a connector: it's supposed to be detached from the white cover and not from the logic board. Anyway, I ended up ripping the logic board attachment off while insisting to treat it as a connector, so there goes the Reset function. But hey, they say "no UI is the best UI" and that's what I got. The only external input and output: Gone
- I intentionally didn't re-attach the bottom screws, because now the unit is faster to pull apart the next time, when the fan needs to be replaced. I bought a replacement fan already from eBay, it will probably be needed in a year's time.
- The bottom rubber parts had to be adjusted slightly to fit nicely around the new fully rectangular HDD shape.
- The top rubber part didn't fit properly due to the fatter drive, so that's now gone too.
These "modifications" didn't increase the 2014 original noise levels or affect the backup operation. The new drive and lubricated fan are much quieter than what I had yesterday. I can still reset and check the status with Airport Utility.
Aligning the hard drive is easier, if you attach it before pushing the contents back to the box. But then it's hard to align the Ethernet connectors to their holes, as it's a tight package. So it's better to put the contents in first, align the Ethernet connectors, and then fish and push the rubber parts to their correct locations before finally pushing the new drive into its place.
I found that keeping the unit upside down (Apple logo up) increases ventilation, and the holes no longer suck dust from the corner it's standing on. Heat rises up and cool air falls down, as physics would want it. This makes the ventilation stay cleaner for a longer time, delaying the need for another fan lubrication, clean-up or replacement.
Overall, not a flawless project, but the new "personalized" model is happily and quietly doing its job again. No warnings from diagnostics, and the fan is stable between 1700-1800 RPM.
