Tuesday, February 2, 2010


I have been working on this mod or derivations of it involving the iMac G4 on and off for a year. Although, I am happy with the result. I have left a sea of burned out lcd controllers, inverters, damaged lcd screens, and parts from broken iMacs in my wake. With the money I have spent on this mod I could have probably purchased a working 20 inch iMac G4, upgraded it to its max, and be halfway towards the purchase of a brand new 27" iMac. I would be lying if I didn't admit that I think about 65 solder joints (most on 30 gauge wire) being pulled every time I move the neck. While I am certainly no electronics expert, I have been modding and working with computers for many years, these LCD screens, backlights, and controllers are the hardest things I have ever worked with. They are so sensitive, so easily damaged, and sometimes they do strange things. So while I would never discourage anyone from doing this project, just know what you're getting into

This has made me come to appreciate the original machines so much more. The fact that apple was able to fit a computer, full drive, hard drive, power source, amp, speaker, and graphics card in the base is incredible. The fact that even years later it is so hard to improve upon this computer demonstrates how great their design is.

Happy Modding


  1. JBerg,
    I was just wondering if you have a list of parts and prices, along with where I could order them, for doing a mod that would allow for the use of the original 17" G4 LCD. I'm not concerned with running the wires through the neck or anything, just want to make use of an iMac with a dead logic board.

  2. Sure, the 17 inch panel model number an LG LM171W02(A4)(M1). TMDS lcd controllers and inverters usually run $60 - 80. One company is www.agilentpixel.com though there are others. They have 2 controllers that have TMDS channels. Thats really all you'll need.

    I'm wondering through where you plan on placing the inverter. If you plan on putting it in the base and not wire it through the neck, Id be concerned about having a high voltage wire so openly exposed. You could place it on the back of the monitor.

    Hope that helps

  3. Is it possible to put a mac mini in the base and continue using the current display? I have the 15" display model and have been looking around. I have not found a single display that meets the requirements. Most displays seem to be 15.4", and not 16:10. If you know any good sights to look at, that would be appreciated. Thanks a lot,

  4. P.S. I just saw that the person above addressed my first question.

  5. Jonathan - just to let you know. The 17" and 20" models are 16:10, but the 15" model is 4:3 and most 15" desktop monitors should fit those dimensions.

  6. That makes much more sense. And to make sure, I can use a controller such as: http://www.agilentpixel.com/product.php?id_product=76
    can I connect this controller to a mac mini?
    I know how to do everything else... except for the display. Thanks for your help,

  7. I have never tried to use the 15" LCD so I can not be sure which controller works with it. However, I am sure there are TMDS LCD controllers that can do it. Just get a controller than has a DVI and connect it to the mac minis mini-DVI or display port.

    Just realize that its not as simple as plugging the cable into the controller board, you will need to do a significant amount of rewiring even if you use the wires in the neck. Also, you will need an inverter for the backlights and you will need to wire that through the neck (Do not use the existing wires to carry the high voltage charge - it will not work).

    Good luck

  8. so basically, I might as well get a whole new LCD. Do you have any preferences? I like the one you have in the pictures, and it looks much brighter than my current display, which is perfect. Again, thanks for your help.

    I have been practicing my soldering, and have come up with a solution for the ports. I will end up cutting a square (or the closest I can get to it) in the center of the old imac's logic board. The mac mini should fit nicely into that. I will use the old logic boards screws and screw it in place, since around the outer edge are the ports that fit perfect with the Imacs design. I have been practicing on my moms old broken Powerbook G4, and have figured out how to desolder ports, so far just USB and firewire. I can then cut, for instance a usb cable in half and connect the wires to the USB port. Then solder that USB port into the Imacs old logic board and connect the other end into the mac mini. I have a working usb port on my moms old Powerbook G4 that works like a charm. Firewire is more difficult, due to the Six wires (for firewire 400) rather than just four wires for USB. Its doable, though. This will be an interesting project, and I probably won't get started until the summer at earliest. I foresee much work ahead, and currently don't have much time. That is why I am researching my options early.
    Currently I am learning how to connect the audio jack. luckily I have the one on my moms old laptop, and I have an Ipod touch that I have already taken apart. I have much work ahead of me, obviously. To save space I may also end up taking the mac minis top case off. This will all be dealt with eventually. Thanks again,

  9. I have 2x 15" ilamps

    I am still confused, Do i need a laptop lcd? or a desktop lcd? sorry. love your work!

  10. For the 15" you should used a desktop lcd as its a 4:3 ratio. Laptop 15.4" lcds are a different aspect ratio. Plus, you'd still have to buy an lcd controller. I'd recommend either using the native 15" display and buying a TMDS controller or using a desktop lcd.

    Thank you for the compliment.

  11. any other great words of wisdom?


    i ordered that.

  12. But sorry for acting dumb, but what about power for a desktop one?

  13. for the 15", what do you think about this screen?


    Thanks for everything you have already done, and what you will do in the future,

  14. actually here is my plan so far.


    use that with the adboard found here


    Only problem would be wiring through the neck so i thank you for your documentation

  15. Fleebailey33 - that is a laptop 15.4" screen, it will not fit in the 4:3 15" housing. You could use a 17" laptop screen which will fit in the 17" housing.

    Also, there are some problems with using a mini itx core 2 duo/quad board in the base. It will be a VERY tight fit (especially with the LCD components). I'd be very worried about heat and ventilation with a LGA 775 CPU and large heatsink. Also, it will be impossible to use a standard ATX or micro-ATX power source (it will def not fit with a motherboard/heatsink/lcd components). I would recommend a pico itx power supply with external power brick. The largest I've seen of these are 200W - they work great - but with a powerful processor you may start to tax it with too many peripherals.

  16. Jonathan, I think that screen looks good. The picture is kind of distorted but the resolution of 1024 x 768 is consistent with a 4:3 screen. You will still need a LCD controller and inverter for this screen. However, because it is an LVDS monitor they should be relatively common. If you need any advice on choosing a particular inverter or controller, please let me know. I'll be working on a 17" version that should be very similar to this shortly. (I have already ordered the monitor) - I will be trying to use as many of the existing wires in the neck as possible. Remember though, you will still need to open the neck to add inverter extensions. I hope this helps.

  17. Hey JBerg, great postings, I really appreciate the time you're putting in to your blog! I'm trying a touch mod of my own on a g4 flatpanel (15 inch) and was wondering if you had any advice. My current plan is to use the lcd included in the mac. I've removed the bezel+panel out of the mounting piece successfully, although I can't seem to separate the panel from the bezel; the plan being to put the resistive touch panel in-front of the LCD. is this a good strategy? the service manual I've read says the lcd panel should separate easily from the bezel after the 4 screws holding it in have been removed. I'm perplexed..

    Any advice would be appreciated

    arthur 5005 @ gmail . (com) - (no spaces)

  18. btw, all the internals are going to remain the same as well so my ultimate goal is to just get that resistive panel in-front of the lcd, and the usb wire down the arm. Although I'm willing to compromise on the how the wire gets to the usb, it has to plug in on the outside anyways.

  19. Arthur, I've never opened a 15" iMac monitor myself. The 17 and 20 inch hav3 3 small torx screws in the bottom that release both the front bezel and the monitor (together) from the rest of the computer. Then there are four screws in the bezel, once these are removed the monitor comes easily out. So to be honest, I'm not sure why its not coming out for you.

    For the 17" the resistive touch screen can fit in front of the monitor. However, you can not screw the monitor back in to the bezel tightly (this will crack the touch screen). so one turn is all you should use.

    In terms of wiring, the 4 wire extenders that usually come with resistive touch screen are long enough to make it through the neck, so you could wire through there (see my 17" NEW NECK post) or simply cut a hole with a dremel in the back of the monitor casing and use that.

    Sorry I'm not more familiar with the 15" iMac, but if you need any further assistance, just let me know. - Jon

  20. Thanks for the response Jon.

    I received my panel today, I haven't had any further success in separating the panel from the bezel, although from what I can tell it feels like there's a light glue keeping them together. I'll be lightly applying a heat gun to the edges to see if that helps in the separation process.

    After the separation I'll be trying my hand at the neck! I'll let you know if I run into any further issues! I'm more anxious to get moving on the software I'd like to write for this thing!

  21. Heat gun worked like a charm btw, panel separated from the bezel quite nicely!

  22. Glad to hear it! I wonder why someone glued it in the first place? I just finished the 17" mod with the resistive panel, it fits and works nicely, so I'd expect the same for the 15". Good luck

  23. I've got a 2 17"G3s. One of them is working fine for one son. The other son has a nice computer, but I'd like to use the other G3 as his monitor since both computers sit on opposite sides of the same desk. It would look more symmetrical.
    I want to keep it simple and since the wiring goes through a hole in the wall behind the monitor I was thinking of just changing the monitor to a 17" white lcd (vesa plate conversion) and using the imac front bezel to make it look the same. The wires do not need to run down the neck since the computer is below the desk. Do you have suggestions for a model of lcd which would work easily as well as directions for how to remove the G3 front bezel.

  24. Hi Richard, I assume you mean a G4 and not the CRT G3. To open up the 17" lcd frame you need to remove 3 Torx screws on the bottom of lcd casing. If I remember correctly this requires a Torx - 6 screwdriver. Just be very careful and don't force it they strip very easily and then have to be drilled out.

    Finding a good LCD for the VESA plate conversion can be tricky. 4 key things to look out for are: 1) Must be 16:10 or the imac front bezel will not fit over it. 2) Try to find one without buttons on the front, with the imac bezel on top you won't have access to those buttons. 3) It must be light - the VESA plate conversion displaces the monitor about 1" forward which compounds the problem. So aim for a monitor without speakers or extra bells and whistles. 4) Must be VESA compliant. The one I chose was the w1707 monitor:


    It was silver on the back (couldn't find white). But it had speakers on it and was too heavy. I had to use a 20" neck to support it.

    If I had to do it over again I'd probably choose the Hanns G, but its black and I can't guarantee anything.



  25. Also Richard, you may want to hold off. If you go to the newer posts in my blog - you will see I am currently working on direct DVI hookups to the existing monitor. I am almost complete with the 17" and am dealing only with some minor sleep/screen corruption issues. Although this does involve wiring. I plan on posting as specific details as a can. Plus, as you already have a 17" with a working monitor with inverter the cost of supplies to do this mod are likely to be very reasonable.
    $15 AC to DC power supply, <$5 in resistors, $5 DVI male connector. What I'm hoping to wind up with would be a DVI cable coming out the back and a DC power brick with a switch on it to supply the backlights and panel. It may be the most elegant solution for you.
    I hope this helps and let me know if I can answer any other questions for you. Jon

  26. I know with the money you have spent to make iMac G4,you could have purchased ready made one.But the thing is the way you have put your efforts in this iMac would never be same in ready made one.

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