Thanks for sharing your build, it would be great to have a few more photos. Just a couple of questions comments.
Is there a reason for your Choice of the older NUC (assume D33217)?
It is very interesting that you can power the NUC from 12V. It was only the Haswell version of the NUC where they officially stated 12V is enough.
Working out how to re-use the main PSU is very good. I haven't seen that done before (on this forum), would be good if you could post more details.
Also how is this PSU controlled between ON and OFF states. In my iMac build I turned the PSU off (via normal ATX PSU signals) so as to not cause further again when computer was off, but still plugged into the wall. Although in truth I wont turn it off, it just goes into standby.
As to your case fan problem, I would be tempted to run it off 5V from the a USB header on motherboard. These should be rated to provide enough power, and a 12V fan will easily run of 5V just a bit slower (and quieter)
Kiwi
Some quick answers, since I don't have a lot of time right now. As I said I have a company so very short on time
- I'm using the DC3217IYE witch runs fine off 12V. I couldn't find it anywhere in the tech specs but I just asked Intel and they told me it should work, so I just went for it.
- The native PSU is always on, so the NUC (just like a regular NUC) always gets a 12V feed. Switching it on sends 5V through the HDMI port pin 18 and fires up the LCD. I spliced the 5V coming of the HDMI cable 4 times (pin 18):
1) To the 'hot pink' from the LCD cable wire to fire it up
2) To DVI pin 16 through 1 kOhm resistor, the hot plug detect (alert: DVI pin 16 is HDMI pin 19)
3) To yellow 5V wire of the inverter through a 6.8 kOhm resistor to fire up the inverter
4) To the white wire of the PSU (and the blue one to ground)
- I won't add the case fan, since there is a huge amount of space in the iMac left. The NUC is stripped from it's case and just sits naked in the iMac leaving lots of room for airflow. I've shortened all cables inside to get out of the way and leave lots of room for airflow. The USB issue is resolved too, cable was too long leaving the keyboard unrecognised upon boot (not always but sometimes). The native PSU is nicely tucked halfway through the case to the sides and I have no DVD drive installed.
I've used the iMac quite intensively today and the temp never exceeded 61 celsius.
I did make loads of pictures, but a bit less in the end when it all became a bit frustrating
having to cut the DVI connector was a bit of a setback as you can imagine. Then the first test results gave me beautiful artefacts
so I kinda stopped taking pics. Like I said I'll make another 20" iMac, knowing what to expect I'll be able to document it better.
Edit: It seems I'm a brilliant modder the way I stated the native PSU bit, but I'm not the one to take credits; it's all thanks to dremeljunky who explains it very clearly on his blog!
Edit2: How do I place pictures inside posts? (img)image url(/img) *replacing ( with [ of course?
