Thursday, February 17, 2011

iMac G4/Cinema Display Mod - Improvements

So far this mod is as close to perfect as I have gotten, but there are a few things that I felt could be improved.  For one - with the touchscreen and iMac bezel in place there is a one area where I was getting "monitor drift" that is the neck would slip down an extra inch or two when positioned in a certain way.  Secondly I did not love that the touchscreen is located in front of the cinema displays bezel or that it was held on by mounting tape.  Thirdly, despite doing a better job hiding the touchscreen wire, I still found it somewhat unsightly.

My initial intention was to make the touchscreen easily removable, but having used this mod with the touchscreen, I would never remove it.  So I decided to integrate it into the display.  However, the 5wire resistive touchscreen although only a few mm thick will not fit under the bezel.

I looked for film to film touchscreens but could only find them in 18.5" or 21.5".  Plus chances are its not a 5wire.  I know everyone wants capacitive, but 5wire resistive is very durable and for the price, very reasonable.  For those interested the screen I use:

The company ships fast and it packages it very safely in a plexiglass lined box.  So here is how to integrate the touchscreen.  Again this is only for people that are using this particular touchscreen.

To start I wanted to decrease the weight a little bit to compensate for the touch screen.  I decided to remove the top portion of the bracket.  Although this gives less surface area for the glue to hold.  The weight is actually supported by the aluminum frame itself - so this part protects from rotation more than anything.  I used cold weld epoxy and am confident that even without the top of the bracket its not going anywhere.  But I still had to figure a way to mount the touchscreen flush against the lcd.

So to solve this I actually cut out part of the front bezel of the apple cinema display.  I positioned the touchscreen in the center, traced around the screen and dremeled that area out.  This allowed me to put the touchscreen flush against the lcd screen and the monitor is still securely held by the remaining bezel.  The touchscreen is also firmly held in place by the square cut for it.

Previous Method
New Method
To the left you can see the difference.   The new bezel is pictured on the bottom.  You can see the front is much thinner as well as having the smaller bracket.

The original method is on top.  Again, unless you are planning on using a touchscreen and it is similar to this one, I would recommend using the original method.

One complication of this is that the Cinema Displays LED indicator gets cut off.  This gave me the opportunity, however, to use the native iMac G4s LED.  As they use different 2 pin connectors of opposite sex, I had to create a hybrid using the LED wires.  I can then plug the LED wires coming from the Apple Cinema Display's Control Board into the ribbon LED from the native iMac G4.  The ribbon cable easily fits between the touchscreen and the bezel.
Hybrid LED cable

iMac G4 Bezel with LED
I then used tape for two reasons.  One, I wanted to make sure the touchscreen doesn't fall forwards (even though its wedged in there very snugly).  And secondly, I wanted to give an area where I could put an epoxy to adhere to the iMac G4s front bezel (without gluing directly to the touch screen), which becomes the new front, replacing the Apple Cinema Displays front which was largely dremeled out.

Touch Screen flush with bezel
The touchscreen ribbon cable now goes internally and thus no cables are visible.  It connects to its 5 pin adapter and goes down the neck to meet the controller in the base. Its difficult to see in this picture, but the touchscreen is now flush with the remaining part of the Apple Cinema Displays front bezel.  Using epoxy the iMacs bezel was attached, sealing off our now heavily modified hybrid case.  The case still opens and closes like the original Apple Cinema Display, but now the touchscreen and iMac bezel are fully integrated.

The best way to see the difference is from the side.  Previously you had Apple Cinema Display with a few mm of touchscreen visible in front then the iMac bezel.  Now the new bezel interacts directly with the original case.  Plus, there is now no visible wire anywhere as everything is internal.

In addition, there is no "monitor drift" - NONE!! Not in any position.  If this is the effect of some weight removal or simply moving the touchscreen inwards a few millimeters - I can't be sure.   But, either way it worked.

As an added benefit the iMac G4s native LED looks great.  Sometimes the little things really do go a long way.

The only negative is that the touch screen is no longer "easily removable".  I decided that really the only use I have for a 20.1" 16:10 touch screen is for this mod.  Plus, after a few days it became clear that this mod is even better with the touch screen (in my opinion) and that I wasn't going to opt to remove it.  I will be posting a full parts list and step by step for this mod.  I will do my best to separate it into with and without touchscreen.

As a side note, you may notice some of these pictures use the apple cinema display that I had painted white.  After looking at the white version, I decided to stick with the original silver of the apple cinema display.  For one, I am not the best painter and it had already chipped in places.  Secondly, the silver really goes and it matches well with apples keyboard/mouse and even the mac mini.  Although using the original display would be ideal, I feel this has some advantages.  The presence of USB (and firewire if you wanted to hook it up), on/off switch, brightness control, more mod friendly (room for longer cables etc.).  As always, questions, critiques etc are welcomed.
Pressing the Cinema Display's Power Button


  1. I like it.

    Does touching the screen wake the mac mini from sleep?

    Have you seen any matte touch screens?



  2. Hey Roger,

    Yes the drivers are essentially mouse drivers, so touching the screen registers as a mouse click. Unfortunately, this is the only "reasonably priced" non-custom 20" 16:10 touch screen I have been able to find, except for a much heavier surface acoustic wave touchscreen, which is also very reflective. I do have to say that when the lcd is on, you barely notice the reflection.

    This is really my favorite mod by far, despite being hooked up to only a 1.8ghz mac mini, this has become my favorite desktop to use. I have been using it with air display for the iPad, as they are both touch screens, you can "pass" windows between screens. And the best thing about this is its stability. I have not have to repair, adjust, modify, or even open this is any way since I completed the final version. Even little things like having absolutely no monitor drift - it makes a difference.

    Even if you forgo the touchscreen for now. You really should do this. I am working on a step by step but it is coming along somewhat slowly. Please let me know how I can help. - Jon

  3. Hi,

    Just wondering if you think I could fit a disassembled 20" cinema display into a 20" iMac (with a broken LCD that'd be removed). I wouldn't need room for USB/touchscreens/etc.


    1. I assume you mean fit the entire contents of a working cinema display into the iMac G4 housing and I assume you mean an aluminum cinema display ) the white plastic one will definitely not fit. For the aluminum one, the answer is still no, but there is a work around. The LCD itself will fit with one exception. The top plate that protects the JAE connector input on the back of the LCD is shaped differently that the native LCD's and does not allow the housing to be closed. You can remove this plate, but just add something to ensure that it doesn't contact the metal back of the iMac G4s rear plate. I added a sheet of styrene and used simple electrical tape to secure it.

      There is more in the cinema display that just the LCD, there is also the inverter and the LCD controller. Neither of these will fit in the iMac's housing, not if you want to be able to close it. However you can use the native inverter in place of the Cinema Display's inverter. However, you need to add an extra wire to the open space in the iMac G4s inverter to get wake from sleep to work. See this post for details:

      The bigger pain is the LCD controller, this has to go in the base, but that isn't such a big deal as its quite thin. The signal is also TMDS which is same as the iMac G4. Unfortunately the Cinema DIsplay's connector has more wires in its connector (I do not know the consequence of not hooking these extra wires up.) There are actually 2 versions of the cinema display and the one I used had 5 extra wires, plus I needed one extra for the inverter. Also, replaced the black cable/TMDS signal cable with the cinema display's TMDS signal cable. I describe this in this post:

      At first this mod housed a Core 2 Duo ECX board with the controller hidden bellow it:

      But then I placed a DVD drive and the power brick in it and connected it to an external mac mini:

      So, it can be done, but you have to be comfortable opening and rewiring the neck to some extent to guarantee that it will work. Hope this helps.

  4. Wow, thanks for such a detailed reply! :)

    It sounds like using the native inverter is the best way to do it. I'm a little unfamiliar with it all.. inverters supply the power to the LCD from some source. So, would I be using the cinema display's adapter with the iMac inverter?

    One of the big reasons I was thinking of using the Cinema Display is that I have one lying around, and it has a DVI out on it, meaning that I could avoid the process of buying a DVI connector and doing the mod to get it working with the iMac's LCD. (My iMac in question has a broken LCD anyway, so I'd be using the Cinema display.) I suppose I should confirm with you that using the iMac's inverter, but the Cinema's controller, would allow me to use the Cinema's DVI hookup? Again, I don't really care about the USB or Firewire ports. I Just want to make a cinema display enclosure out of an iMac G4.

    What you've said sounds pretty straightforward, so I think I'll give it a go once I'm done my spring courses. Thanks very much for your advice. Best of luck with your future projects! :)

    1. Sure its my pleasure. To be honest using the cinema display does have its advantages, such as the ability to control brightness as well as a better LCD and works as a Firewire 400 and USB 2.0 hub. The controller itself doesn't convert the signal, like most do, as this TMDS LCD has another controller in the LCD itself which does that. You'll notice that the actual TMDS signal wires (the 4 pairs of 3) don't actually go to the LCD board but go right from the DVI to the LCD. Now the other 5 wires which go to the DVI (I suspect these are a Ground, Hot Plug, VEDID, Clock, and Data) go to the board. The board then sends the power (3), grounds (3), VEDID, Clock, Data to the DVI. But, there are also 6 extra wires - one of these is a ground. I don't know what the others do. You could try to use the existing microphone and led wires in the neck (5 wires) to make up for some of these or you could do what I did and add an extra gray wire.

      The inverter turns the low voltage DC power into high voltage AC (the voltage going from inverter to the LCD can be dangerous). The native inverter seems to function exactly like the cinema displays inverter. You do need to add an extra wire however as noted - in the empty slot, or sleep won't work properly. Its a fun project and once you get it working its very stable and works no differently from a native cinema display. You even have almost the entire base to work with, save for the thin LCD board. I put an internal drive with SATA to USB, the white power brick (which I connected to a C13 to C5 electrical adapter so I have the original appearing outlet and plug on the back), and a rocker switch for the drive. You can also keep the touch controls, but you do not need them.

      Let me know if you need help along the way.

    2. Hi Mr Junkie,

      i'm planning to buy an imac g4 20" dead (motherboard + screen)

      - i want to put the mac mini in the base (pretty easy)
      - i want to change the screen. there are 2 options:

      1) remove the old screen and screw the cinema display to the neck like here (without the sensitive mod) = is it stable enough? i like the possibility to change brightness. is it possible to put all the cables in the neck? i'll just glue the bezel in front of it

      2) buy another LED screen which would fit (what are the dimensions of the screen case?) to me its the easier way..

      thank you!