Thanks Ersterhernd for the replies. Im starting to order some parts now. Boy you guys are right. Space is at a minimum. What makes it hard is the centralized 2 main fans. I've been trying all sort of schemes for days. I think I've settled the best layout possible. On the HDMI conversion did you use the 1K resistor?
As far as PSU. Since I'm not using a NUC board I don't have on/off pins. My idea is to utilize the laptop power on circuit board to turn on the MB. Even if I after relocated the power button. Then figure out how I can get 5V to this relay from the board to get the other PSU going. All I have is a cpu fan connector, micro SATA on board connector, and a battery female push pin connector underneath MB. Perhaps steal the 5V from USB? Are all USB powered by 5V? Does it have to be 5V, can it be 3V relay? Testing battery terminal, I got 3+V on 3 pins.
When you spliced the AC lines from the NUC adapter in the iMac PSU, does that mean the NUC power adapter inside the iMac is always on when the iMac is plugged in?
If I were to use lets say only the PSU from laptop 90W or upgrade to 120W, can I split the barrel, and use one to MB and the second out to a boost 19V to 24V to inverter? Does splitting cause 19V 3.5amp to drop?
Yes I used a 1K resistor on the HDMI. I've done several of these machines and settled on a method that although wasn't pretty to look at, worked very well and was considerably easier dealing with the required soldering of such tiny wires.
The link is
here.
There must be a way to wire the iMac power button to the laptop board power button. There are traces on the corner piece of the iMac board (you've cut it already) that trigger on/off. You'll need to test for zero resistance while pressing the button to find the correct traces. Its a feature I'd go to great lengths to preserve.
The relay I used is definitely 5V as per the specs. USB will give you that, but stays powered during sleep mode, although it may work to accomplish on/off to the relay.
The NUC power brick remains 'on' the same way it would if plugged into the wall in a normal NUC application. Its designed to do this, not to be unplugged after every use. The NUC PSU was just small enough to fit and actually touches the inside of back cover of the iMac when installed.
Splitting your 19V and stepping up to 24V at the barrel connector will feed the full 24V to the inverter all the time. I think the 24V line in the iMac PSU only puts out 20V or so when 'off'. You may need to figure out some way to circumvent that for proper inverter life. I'd try to re-use the iMac PSU if at all possible. It not only will feed you all the required voltages, but it contains the AC power socket that you'll require for use of the iMac power cord.
The pic you've attached of your layout shows that your laptop board uses about 2x the real estate of the NUC. I'd continually test the installation of the back cover throughout your project. It MUST fit on properly when complete, the heavy hinge assembly takes up a lot of room, and there cannot be any shorts to the metal case.
Good Luck and keep going!
Cheers
Ersterhernd
