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Ersterhernd's NUCiMac G4

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Build Log 6 - LCD Display

This is by far the most challenging part of the entire project. Credit goes to the Dremel Junkie for his comprehensive tutorial at this link. This step in the project was perhaps one of the most difficult tasks I've ever completed with computer hardware. Getting the HDMI video signal from the NUC onto the G4 LCD was a tremendous challenge.

EDIT: More than 8 months after the completion of this build, I changed the wiring slightly as shown in the table below. I discovered in a later iMac G5 project that this 17" LCD requires 3.3V to the VEDID wire (as per the mfr spec), not 5V as is supplied from the DVI. It was a tedious task to repair, but may save long-term damage from over-volting pin 15 of the TMDS. The good part is, it is actually easier to wire the LCD this way, as opposed to the "Y" method used previously. Essentially the changes are as follows:

1. Connect Pink wire from grey LCD cable direct to 3.3V from the PicoPSU.
2. Connect DVI pin 14 and DVI pin 16 via 1KOhm resistor.


(Note that the iMac G4 and iMac G5 17" models are wired identically)

4lcz.png



There are two video cables that come down into the G4 dome from the screen; the inverter cable for backlight and the LCD cable for video signal. Both require connections to either a DVI connector and/or a power source, in this case being the PicoPSU. I highly recommend reading through the Dremel Junkie's website for a complete and comprehensive tutorial on this subject BEFORE starting this step in a G4 iMac build.

The first realization I made was that I needed several extra wires to connect the LCD. There was a method of shortcutting by splicing into existing LCD wires, but it was risky. These wires are hair-like strands that are extremely fragile. The only place to find the required wires was in a second G4 iMac. I decided I wasn't going to risk damaging my NUCiMac LCD cable, so I found a non-working G4 on Craigslist for dirt cheap. Another option is that iMac necks are readily available on eBay as well, but this was very convenient.


Stealing the LCD cable out of the second (non-working) G4.

IMG_3963.JPG



These are the extra wires I needed from the 2nd iMac

IMG_3950.JPG



This is my existing NUCiMac LCD cable ready to connect. Disassembly only took a few minutes.

IMG_3933.JPG





I set to work, following the Dremel Junkie's guide to the letter. I used my other NUC build (G4 Cube PSU) to test the connection via HDMI. Here's what the workstation (our kitchen table) looked like for the operation.

IMG_3957.JPG





I constructed the new DVI connector wiring with alligator clips first to verify functionality. The DVI connector and HDMI adapter were secured down with heavy velcro so they would not move. These wires are VERY delicate. There are 17 in total to connect to the DVI, and two that are connected to the PSU.

IMG_3953.JPG



Alligator clips would later be replaced with soldered connections after functionality was successful.

IMG_3955.JPG



The PSU connections. This will be a PicoPSU when the build is done.

IMG_3954.JPG



After a couple of mentally exhausting hours, I connected the HDMI from the Cube PSU machine and here's what happened :thumbup:

IMG_3951.JPG



The final step was to solder, package and securely mount the final assembly in a location where is was safe from movement or damage.

IMG_3959.JPG


IMG_3960.JPG



HDMI Cable attached. Mission Accomplished!

IMG_3961.JPG


IMG_3962.JPG





Ersterhernd
 
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I send thanks to MiniHack and iCubeFan for assisting with this idea.

Ersterhernd
Thanks for the mention I was just a mere messenger ;)



I haven't figured out the ethernet port yet, as there is VERY little space on the right side of the power plug
Ersterhernd

I think an Apple USB Ethernet adapter would fit in there, maybe you need to dissasembly it.


Cheers
 
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Wow, that is a complicated wiring job.

Does the display also have a USB connection going up to it like the old studio displays do? I re-wired a 15" Studio display but didn't bother with the USB connection - as I thought it was just for the hub - and then found there needed to be one to the controller board which did the brightness via sys preferences. At that point I had already shut the back up and couldn't be bothered to take it apart again!!!
 
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Ersterhernd,

Another bang up job. You are going to be disappointed/flattered to hear that this is my next project as well. My brother had an old 15 inch iMac that he let me have - it is a bit used looking so I may go online to grab one with a nice looking case instead. How difficult is it to buff scuff marks and the like out of the case? Mine is sitting in the US and I live in HK - waiting for Christmas to get to work on this thing. I am also planning on seeing if I can get a touch screen in there and either dual booting Windows 8 or running it in parallels as I understand that parallels has support for multi touch these days. Again, nice work and I enjoy having you as my lead blocker on these things.

Spence
 
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Wow, that is a complicated wiring job.

Does the display also have a USB connection going up to it like the old studio displays do? I re-wired a 15" Studio display but didn't bother with the USB connection - as I thought it was just for the hub - and then found there needed to be one to the controller board which did the brightness via sys preferences. At that point I had already shut the back up and couldn't be bothered to take it apart again!!!

LoL I can fully understand wanting to leave this all put together once its done. Theres no way I'd want to pull all those wires apart after having them work. You have no idea how relieved I was when this screen lit up and booted OSX. There's SO MANY wires, I could never retrace all my steps. It amazing how JBerg figured all this out and 'tutorialized' it.

No USB in the iMac G4 screen, several down in the dome though. I love the old high-powered Apple USB ports. Great for the Cube Speakers!


The project now continues with the hardest part in the rear-view mirror. Phew!!!



Ersterhernd
 
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Ersterhernd,

Another bang up job. You are going to be disappointed/flattered to hear that this is my next project as well. My brother had an old 15 inch iMac that he let me have - it is a bit used looking so I may go online to grab one with a nice looking case instead. How difficult is it to buff scuff marks and the like out of the case? Mine is sitting in the US and I live in HK - waiting for Christmas to get to work on this thing. I am also planning on seeing if I can get a touch screen in there and either dual booting Windows 8 or running it in parallels as I understand that parallels has support for multi touch these days. Again, nice work and I enjoy having you as my lead blocker on these things.

Spence


Hi Spence, you'll find the G4 iMac a VERY interesting build. Its about 75% wiring challenge, 25% repurposing. There are lots of these on Craigslist locally here. With the 15" you get less resolution obviously. The 17" gives 1440x900 which is nice. The 20" models are choice, but create power issues in these builds due to a 24V power requirement. From what I've read, you have to leave the stock G4 PSU in place; don't quote me on that though.

I know you'll enjoy the challenge, no matter what size you go with.


"Lead Blocker"... LOL :lol:


Will have more updates in the coming days.


Ersterhernd
 
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Build Log 7 - Audio

The Intel NUC DC3217IYE doesn't have an onboard sound chip, however, it supports both HDMI audio and USB audio. I chose to implement a USB Audio solution, as I had a set of modded iMac G4 speakers (the Apple proprietary plug is removed) and a 20W amp here ready to go. The setup sounds terrific, and uses a standard 3.5mm audio jack to connect to a computer. I figured it would be perfect for this NUCiMac build.

IMG_3967.JPG




This of course required a 3.5mm jack on the NUCiMac, which didn't exist. I started by removing the Apple proprietary jack from the rear I/O, leaving only a nice round empty hole, which needed a little filing out to the size of a 3.5mm audio jack. I went onto NCIX's website and found an OSX compatible solution that looked great and was on sale for only 8 dollars; its the SYBA SD-CM-UAUD USB Stereo Audio Adapter, shown below.


screenshot_104.jpg



It installed perfectly, and lined up great with the rear I/O hole. I'll connect it to one of the two USB headers on the NUC motherboard. A couple of dabs of JB Weld holds it firmly for the stress of plugging in the 3.5mm jack from the exterior.


qljb.jpg


IMG_3969.JPG


IMG_3970.JPG





This was an easy, inexpensive solution that allowed the use of the original iMac G4 Pro Speakers. The sound quality and aesthetic appearance is exactly what I was looking for.


Ersterhernd
 
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Hi Spence, you'll find the G4 iMac a VERY interesting build. Its about 75% wiring challenge, 25% repurposing. There are lots of these on Craigslist locally here. With the 15" you get less resolution obviously. The 17" gives 1440x900 which is nice. The 20" models are choice, but create power issues in these builds due to a 24V power requirement. From what I've read, you have to leave the stock G4 PSU in place; don't quote me on that though.

I know you'll enjoy the challenge, no matter what size you go with.


"Lead Blocker"... LOL :lol:


Will have more updates in the coming days.


Ersterhernd

Different volt needs in a build like that can often be overcome by an external brick combo and then a DC-DC board. For instance for a planned future build I have a 24 volt external brick (actually a chinese power supply for powering LED strips - you can find high power supplies on eBay easily) and then internally you can have something like this:http://linitx.com/product/dcdcusb-intelligent-dcdc-converter-with-usb-interface/12679 which will take your 24v and convert it to e.g. a 19v input or a 12v input to work with an NUC or a Pico PSU - that way you can with a single external power brick do a huge amount of different voltage combinations at a sensible power level dependent on what you want to achieve.

I'm working on another compact build (might be a scratch build or a Cube - not sure yet) where I need some serious power but want to keep out the heat and this is one way to do that.

Feel free as ever to borrow and improve on these ideas!
 
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Looking good! My friend's got one of these, and his dad offered it to me before I got this laptop. Maybe I'll see if he and I could do a project like this. I was thinking about just asking for it and trying to convert it into a monitor/USB hub combo. I'll have to look up the NUC first though.
 
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Looking good! My friend's got one of these, and his dad offered it to me before I got this laptop. Maybe I'll see if he and I could do a project like this. I was thinking about just asking for it and trying to convert it into a monitor/USB hub combo. I'll have to look up the NUC first though.

Thx Metalsonic! The iMac build is very challenging and very rewarding. The NUC is perfect for the job...



Cheers!
 
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