Update - The Native Inverter and LCD Glass

First let me start off by saying that I did something very stupid despite me writing not to do this time and time again.  I soldered the DVI connector on without putting it through the hole in the dome.  So I had to cut and resolder and for those of you that have never seen the components of the black wire of the imac neck, I can tell you it as an absolute nightmare.  They are composed of 4 wires in which are 3 wires; a red (+), a green (-), and a ground.  The red and green wires have a small plastic coat surrounding a single wire that is the size of a hair. When I set up this initially I had the bottom pins on and was able to use a tiny dab of solder, having to resolder these tiny wires, wire to wire has caused signal problems.  Keep in mind even one failed connection will give you no image whatsoever, so a multimeter is very helpful.  But poor connections or poorly shielded connections will result in color distortion.

That said there is some very GOOD news.  The native LCD for the Apple cinema display (LM201W03) needs to be modified to fit and although it fits, I decided to try the native iMac G4's (IDTech 20.1") lcd glass and it also appeared to work (though until I have a perfect image I can not confirm this 100%).  So it is possible that the only thing you may need is the LCD controller board from the apple cinema display and the cable to get this mod to work as the native G4 inverter has been confirmed to work and the native LCD glass appears to work.  This would be quite helpful as you can use a broken cinema display with a cracked screen.

 To the right you see the mod to date.  The top monitor housing closes as easily as the original as it uses the native inverter and the native glass.  Because I wanted this mod to be as close to the original as possible - I actually purchased a new monitor housing and base cover from ebay as most of the broken used iMacs I have acquired tend to be yellowed or scratched.

You can see the monitor from the front, side and back.  To the right of that is the lcd controller and ECX motherboard.  The ECX boots from a compact flash card located on the underside of the board.

The ECX board is the size of a 3.5" drive.  My plan is to mount the ECX board on top of a blu ray drive in the native drive caddy.  (essentially taking the place of the native hard drive).  As the CPU fan will be sitting at the top of the dome, I will not need a fan, so I should be able to fit Wifi and Bluetooth at the top of the dome with the vent holes.  As I will not be using the native power supply I should have room around the ECX board to fit connectors.  The lcd controller board will replace the native iMac G4's motherboard at the bottom of the dome below the drive.  As its smaller than the native motherboard I'm hoping to have room to wire up some rear I/O ports.  The only downside is that this leaves no room from the power supplies for both the monitor and ECX board.  They would fit in the drive caddy and using a splitter a simple AC plug could be placed in the back, but then obviously there would be no drive.  I have thought about using the native iMac's power supply, but I really need the room and in a similar experiment I fried a different ECX board in the past.

So, I'm going to keep them external.  For one the power supplies are small and this is a desktop computer, it won't be moved that much.  Plus, I have always loved the drive and by using blu-ray it can be useful.  Also, its gonna be tight in there and there is really no cooling system in place - so keeping hot power sources external is probably for the best.

I do think the system is likely to be hackintoshable - the chipset has been hackintoshed before (this is the Quanmax KEEX-4030 ECX board for those interested).  The thing that I have never heard about is booting snow leopard from a compact flash card - a 2.5" or even 1.8" SSD may have to be shoehorned in somewhere if hackintosh is your goal.

Here is the system booting (again notice the small resolution during the boot that I previously discussed).

This is where the frustration set in - with windows booting.  While I previously had a pristine image, after the resolder, the colors are unfortunately off.  A multimeter revealed all intact connections but I was getting some week noise at the wrong pins - so I suspect some interference or crosstalk.  I'm going to remove all the solder joints for the black wires and try redoing them with fresh connections and extra shielding.

To do this mod, I actually used cables from the necks of different iMacs.  There are the black and grey cables that carry the DVI signal, however the apple cinema display has "extra wires".  Some of these probably aren't necessary, but some of them are.  As a result, I had to add an extra grey wire from a different iMac.  I replaced the native LED/Microphone cable with this wire.  The wiring is somewhat difficult to explain.  If I continue to have difficulty with the black wire of the native iMac, I will likely change it to a different wire.  Likely either the equivalent wires from the apple cinema display or another grey wire.  Both of these choices would be MUCH easier to work with.  Either way when I do finalize how I wire the neck, I will post specific instructions.

While I am quite proud of some of the previous mods - this mod is actually much simpler and besides having to push some wires through the neck, a lot less labor intensive than previous mods.  In addition, if it does turn out, as it seems, that either LCD panel can be used, combinations of discarded iMac G4's and apple cinema displays can be used.  I would NEVER tear apart a working iMac G4 and couldn't bring myself to tear open my mac mini to try to fit it in the base.  I even hated even using a working apple cinema display in my previous mod.  Its always great to re-purpose otherwise useless parts.  But whats great about this mod is that there are so many different ways, but this one feels the closest to the native 20" iMac G4 that I've come so far.

Keep in mind that the KEEX-4030 uses the same Socket P Penryn Core 2 Duo chip thats in the previous and current generations of minis.  This ECX board is no slouch.  That said, if there was a problem with it, I think this is the mod that I would open up a mac mini for and try to put it in the base.

I'm hoping to figure out the wiring, clean up the image and start putting the base together this weekend.  But, as always all comments and suggestions are appreciated, but please no comments about seeing windows on the iMac G4 - Its the only operating system I currently have on a compact flash card.  Also feel free to ask any questions.

The Two 17" iMac Necks

*NOTE: The Inverter Charts have been updated.  As I noted earlier, a reader noted flickering of the backlights with 12V connected to the RED line and it stabilized when connected to 5V.  I initially thought there was some inverter variation but after another confirmation from a reader I checked my old notes and had clearly written "Red - 5V".  I made a mistake when putting together the Inverter diagram for the blog.  Thank you to my readers and my apologies for any inconvenience.  Please note the charts have been corrected to reflect that RED is connected directly to 5V for both 17" iMac necks.

So I have fairly intact versions of both of the 17" necks and they are VERY EASY to tell apart - even if you don't know which 17" iMac the neck originally came from.  They are also VERY DIFFERENT - so know which one you are using before proceeding.  These are the only two part numbers for 17" necks I have been able to find.  Other variations or small differences may exist, I can not be certain.  Remember, you always have the option of opening up the monitor and looking at the JAE connector.  Because they all use the same LCD, the pin number/position will always be the same.  I will focus on the differences.
My previous post/17" pinout detailed what I will call:


NECK A: This is part #661-2825 and is the for the 1ghz and 1.25ghz 17" iMac G4.

 Here is a picture of the JAE connector.  Notice that the pins are glued onto a black board which is then encased in a silver connector with prominent push clasps on the sides.

 Here is the inverter - LCD side.  Notice the colors from left to right (Blue, Black, Red, Green, Purple, ORANGE)

 Bottom of the inverter again you can see the presence of an ORANGE wire

 The bottom of the video cable that plugs into the motherboard had this number on it (620-2305).  I don't know if this is universal across all of these necks, but I wanted to point it out).

DVI pinout A - 1 or 1.25ghz iMac neck

Inverter Pinout A: 1 or 1.25ghz Neck

So here again is the DVI and Inverter pinouts for Neck A recognizable by:
1) Part #661-2825
2) Comes from a 1 or 1.25ghz 17" iMac G4
3) Has a black/silver JAE 30 pin connector to LCD
4) Has an Orange Wire in the inverter cable
5)??Has the number 620-2305 on the motherboard side of the video cable

NECK B: This is part #661-2716 and is the for the 800mhz 17" iMac G4.

I have peeled back the aluminum foil, but you can see that the JAE connector that connects to the LCD is one where the pins snap into a beige connector and there are no clasps on the side.

Here is the inverter (LCD side).  Notice the colors from left to right (Blue, Black, Red, Green, Purple, OFF-WHITE) 

 The bottom of the inverter (removed from connector) again shows the OFF-WHITE colored wire [NOT ORANGE].  There is also a number on the motherboard side of the video cable.  Again, I'm not sure how specific this is.  (620-2122).

So here is the new TMDS to DVI and Inverter pinouts for Neck B recognizable by:

1) Part #661-2716
2) Comes from a 800mhz 17" iMac G4
3) Has a beige JAE 30 pin connector to LCD
4) Has an Off-White Wire in the inverter cable
5)??Has the number 620-2122 on the motherboard side of the video cable

DVI pinout B - 800mhz iMac neck

Inverter pinout B: 800mhz neck

*** I have come across a neck that has the LCD cable of a 800mhz iMac, however, its inverter cable has an orange wire.  As I obtained this second hand, this could have been the result of a repair and may not be standard.  As both are left floating, it doesn't matter for the inverter, however, I can now have doubts if this can be used to differentiate the two necks.  Luckily, there are other differences.

Conclusion:
There are so many differences, there is a Brown cable in one, an Orange in the other.  The order of the rest of the wires is completely different.  Even the Clock/Data cables are reversed White/Black.  While I myself have set up Neck A, a reader of my blog has gotten it working with neck B.  Obviously the color of the wires really doesn't matter its what pin they connect to thats important.  As there may be a slight difference in what I call "blue vs. purple" etc.  Here is a close up of the 2 JAE connectors and the order of their wires (pin 1 position is on the left to pin 30 on the right).

NECK A: 1 or 1.25ghz 17" iMac

I'm excited to see some of the projects people come up with - I also like confirmation that things are written clearly and are correct.  So comments are appreciated - thanks.  Good luck and feel free to ask any questions.

17" TMDS-DVI Neck Variation

There are indeed two different types of 17" iMac G4 necks and the wire color does vary between them.

1) Part # 661-2716.  This neck comes from the 800mhz 17" iMac

2) Part # 661-2825.  This neck comes from the 1Ghz and 1.25Ghz 17" iMac

I believe that thee are the only two variations that exist, as I have not been able to find any different part numbers for iMac 17" necks, though I can not be certain.

I am fairly certain that my neck came from a 1.25Ghz machine, so those modifying a 1 or 1.25Ghz iMac should be able to use the pinout I have posted.  However, those modifying an 800mhz will have different colored wires.

As of right now, I would still recommend opening up the monitor and looking at the JAE connector and following PIN NUMBER instead of WIRE COLOR.  As the LCD panels are the same the pin number will always be correct.

I am trying to obtain a completely intact version of each of these necks to detail the differences and will post the differences when I do.  Several people have gotten this working, while others seem to be having some trouble.  I will try to go through this step by step and post detailed instructions of how t connect this.  I will also try to do it using a spliced DVI cable as most people seem to be going this route.

I am also working on the step by step for the cinema display 20" mod for those interested in doing that

Completed Mod - The 20" iMac G4 / Apple Cinema Display Touch Screen Mod

I am thrilled with how this mod came out.  Not only does it look great, but I really believe that it will stand the test of time.  It is rock solid stable and an absolute pleasure to use.  And to be honest, relatively speaking, the mod was not that difficult.  It can be done in a few days.  For those interested, I can give very detailed instructions.

OK, I wanted to make it this all-in-one BADLY! But, after almost shorting out my itx mobo, I was in no mood to open the mac mini up and put it inside.  That said, the older generation mac mini would likely be superior to the mini itx in terms of fit.  However, the new mac mini is a no-go without serious modification to the internal faraday cage.  For now I am going to keep the mac mini external.  I may revisit this in the future, but for now, I put the power adapter, touch controller, and usb hub into the base.  I was also going to add the griffin powerwave adapter, but am considering trying to track down an iFire adapter (if the price isn't astronomical).  They both power the Apple Pro Speakers. but the iFire doesn't require external power.

Here are several additional pictures:
    The ports on the back are simply a USB (to connect the USB hub), an AC cord (the cinema display power adapter is at the top of the dome), and a DVI.


The 5 wire touch screen cable is still a little but of a work in progress.  I'm confident that Ill be able to hide it under the front bezel, but I am likely going to have to cut into the ribbon cable.  Because I do not want to damage the 20" touch screen, I have purchased, a much smaller 7" 5 wire resistive touch screen to experiment with.  But for now, this works fine.

This mod has really been my favorite so far.  It feels exactly like the original iMac to me, plus the touch screen.  This was certainly not the direction I expected to go when I restarted this project, but am very happy where I wound up.  Again any comments or even constructive criticism would be appreciated.  Thanks again and happy modding!!!

Update: Touch Panel wires hidden under bezel

Wiring the Neck

5pin connector

Cinema Display TMDS

 To wire the neck there are really two choices. 

OPTION 1: You can replace all the native iMac wires with the apple cinema display wires.  The advantage of this is that you don't have to solder the very small wires.  I simply removed the tmds wires (using a safety pin) from the JAE connector and 5 pin connector put them through then reconnected on the other end.  Only on the 3 wire power cord and the 4 wire USB cable did I have to cut off the connector and resolder at the other end.  However, getting the wires through is a huge pain.

TIP: Put the wires through the base first because the DVI connector is too big to fit through the opening.  so once you solder its too late.

To open the neck I again used a taped together mini screwdriver set.  It is not difficult once you get the first turn done.

So open and replace the wires.  (I'm using a neck from a previous mod - so the wires pictured may be unfamiliar).

Getting the wires through can be very difficult.  My advice would be to just bite the bullet and take the spring off its moorings put the wires through and then get it back on once completed.  Sometimes using a small wire to put through then wrapping around the actual cable and pulling through can help.

OPTION 2: Hybridize with the native iMac wires in the neck.  There are the 4 triplet pairs which carry the TMDS image (This is the top of the TMDS connector pictured at the top of this page).  The wires at the bottom of the image actually come from the control board so do not need to go through the neck.  There is an additional 5 pin connector (pictured above) that comes from the DVI and goes to the control board.  Although I haven't verified I suspect these are the hot plug, vedid, clock and data edid, and ground wires.  Although these are a slightly larger gauge than the wires in the iMac gray wire - they should carry the signal fine.  (you will need only 5 of these wires).  The iMac's inverter cable should work fine to carry the USB signal.  Unfortunately the power cable (and its 3 wires) carries 24V and none of the existing wires are adequate.  However, you do not need the microphone/lcd light cable, you can remove it.  This leaves room for the Cinema Display's power cable.  Like the above option, you do have to cut and resolder the cable.  The only one I'm not 100% sure about is the smaller gauge iMac gray wire carrying the wires from the 5 pin connector.  If that doesn't work, I plan on using the inverter cable to carry that signal and will replace the gray wire with the USB cable from the apple cinema display.  Below is the resealed neck with the Cinema Displays cable in place.  Of note, be careful how much cabling you leave on the monitor side of the neck.  Its still a tight fit in the monitor housing.


Getting through the one cable in place of another is not difficult.  However, the challenge is that it will require soldering on both ends.  So the tiny TMDS signaling cables 4 x 3 = 12 will need to be soldered on both ends = 24.  The five 5pin connector x 2 = 10.  The USB x 2 =8.  Its certainly doable and I will post when this method is verified.

20" iMac G4 Mod - TMDS to LVDS (Not Recommended)

UPDATED (11/5/11): I have condensed all the posts that involve this mod to this post for better organization.  Again this method is unstable and potentially dangerous.


This method is no longer recommended as I have since found much better, cheaper, and safer. ways of doing this. there is a safety issue and I do not want to see anyone get hurt.  I am tempted to take this post down but I do believe there is value for people that want to convert from TMDS to LVDS.  The dangerous part of this is the inverter wires.  As I placed the inverter in the base I lengthened the wires that connect from inverter to backlights.  Once the current passes through the inverter it becomes very high voltage.  The 20" version has 6 backlights when you add these cables (12) to the LVDS cables - you have to run more wires through the neck than it can really hold.   What this results in is wires that are rubbing against the hinges of the neck.  I started hearing an electrical humming sound and became concerned enough to disassemble this mod.  Recently I decided to open the neck apart to salvage some wires for parts.  I saw clear evidence of wear to the shielding of the wires.  If the shielding wears on the inverter wire it could easily arc to the metal neck and electrocute anyone who touches it.  Here is a video someone has made demonstrating the ability of the high voltage in the inverter to backlight cable to arc.
Inverter CCFL video

Original Post:

Completed LVDS 20" iMac G4

I. Overview

The biggest question is if you want to use the original monitor which uses TMDS signaling or replace the monitor with one that uses the more standard LVDS. I decided to replace the panel with a standard LVDS panel.

The next decision is size, I decided to go with the 20 inch iMac here. Some people prefer the 17 inch model, but its all personal preference. As long as you are careful about monitor choice this mod is actually easier on the the 17 inch model. Remember to choose a panel that is 16:10 not 16:9.

I ended up going for the LG 204WT. Its a good monitor, has the right aspect ratio, and because I burnt out my last one, I had spare parts. I ended up finding a refurbished one for $90 on ebay. This monitor has some other nice features for the mod. It has a small keypad (the power and menu buttons), it uses an LVDS wired cable, not a ribbon cable, and the power source can fit into the base. Because the base has four brackets that come down around the DVD drive, you can use this as a guide to see what will and will not fit. So if its bigger than a 5.25 Drive its prob not going to fit.

Another decision is to make this an all in one or not. Because the power source and inverter need to be in the base there is little left over room for any computer components.

There are instructions on how to take apart the iMac G4 online and I won't go into specifics but to say you need to seperate the neck from the monitor and base. Almost everything in the base will not be used for this modification. Most of this mod revolves around the neck. To take apart the neck I used a mini screwdriver set and taped two together. You may need two sets and someone to hold the other side of the bolt steady while you turn initially. The neck is not difficult to take apart. This is shown below:

Tape 2 together for 2 sets

II. Wiring
Again, Do not wire the inverter to CCFL through the neck.  It is OK to keep an inverter in the monitor housing and lengthen the cable to the inverter.  But, I can no longer recommend lengthening the wire from the inverter to the CCFL backlights through the metal neck as this is a high voltage wire and there is risk of this arcing to the neck and electrocuting anyone touching it when this happens.


Remove all of the iMacs native wires.

You should first put through the inverter extensions as they are the thickest wires.
The small two pin inverter connector can fit through the neck and does not need to be removed.

There are 6 CCFL backlights (each with a high and low voltage line). The 4 pin cables support 2 CCFL lights and the 2 pin cables support one in the 20 inch monitor. For the high voltage lines, I decided to use heavy shielded inverter extension cables. These wires are very high voltage and high voltage can arc if exposed. The last thing you want is an exposed wire arcing in a metal neck. It can be VERY dangerous. I bought 6 inverter cables from an HP Omnibook on Ebay. They are 15" It takes two extension cables that link in the neck to make it all the way through..

If you decide to use an LVDS panel, you should replace all of the wiring in the neck. LVDS uses a series of paired wires (for the most part). Most LVDS cables have a 30 pin connector of which usually 27 wires are used. In addition, you have to lengthen the inverter wires, that is two wires each for the two inverters. You also have to lengthen the low voltage lines for the inverter as well. As you can see that makes a total of 39 wires that have to go through the neck. Things will get VERY crowded in there.

Remember to be cautious with an open neck, the spring can be dangerous. As long as the neck is open you should tape it down.

For the LVDS cable, you can either order an LVDS cable online or you can make your own. You can use 30 gauge kynar wire. Because I had several LVDS cables from previous mods, I decided to use these. I ran 27 70cm LVDS wires through the neck. The advantage to using LVDS cable is that they already have the pins on them, which makes soldering easier. You have to remove all the pins from the connectors, you can only fit wires through the neck, connectors will not fit. (Except for small inverter connectors). As you run the cables in make sure you label them on EACH END. You will need to know what to solder where.

For the low voltage inverter cables I chose CAT5 wire, I simply cut apart an ethernet cable, stripped it and ran the wires through the neck.

 

With the LVDS wires through

III. Soldering
With the 27 LVDS wires, the 8 + 4 inverter wires through, you can close up the neck in can be difficult to close and you may need to use your screwdriver as leverage. You should try to add shielding to as much of the wiring as possible. However, this is difficult as there are so many wires.

Soldering the LVDS cables

I ran the 27 LVDS wires through the neck, however they need to be extended at both ends and end in connectors. I soldered the top (monitor part) to another 50cm LVDS wire and then the bottom to the existing LVDS cable that came with the monitor. If you do not have extra LVDS cables. I'd recommend simply running 120cm of Kynar wire through the neck, then cutting the existing LVDS cable in half and soldering each wire to its appropriate match at each end. Remember to label all the wires.

I also decided to cut off the 4 pin inverter connectors from the native iMac G4 panel and the native inverter (I did not want to have to cut the wires on the LG panel to attach. I then attached these connectors to the the inverter cables. Pink cables are high voltage, white cables are low voltage.

Soldering the inverter attachments

This is a good place to check the connection. Disassemble the monitor to expose both LCD controller board and the inverter and power source.

First I tested the connection.

Then I added the inverter cables.

 In both tests there was a clear image that ran through the neck. Now that we know it works, we can assemble the base.

IV. The Base


Run the wires through the base and screw in the neck. Connect the wires to the LCD controller and place it at the top of the dome.

Then connect the inverter cables to the inverter and power source. Use screw to attach the power source to the dome.


For the drive, you have to modify the cady, cut the top off (where the hard drive would normally sit). Leave only the side rails and attach them to the drive then screw in the drive. This way the monitor components are protected at the top of the dome.

Wires at Top of Dome

LCD Controller Installed

Power Board Installed

Ready for LCD

You will need to tape the wires flat against the back so you can close the monitor eventually. Its not pretty, but it works.  Close up the monitor and we're done.







Although this mod does not leave room for the touch screen, I can say that I am significantly happier with the way this turned out. This mod leaves me with an external blu-ray player and plug and play monitor. It is clean and simple without any visible wires or shelves on the back of the monitor.  I know this does not show every single step, so if you have any questions feel free to ask.