Friday, October 21, 2011

The 17" iMac G4 to DVI - The Easiest Method Ever (So Far)


For full details please see this post:

GUIDE: Step by Step 17" iMac G4 TMDS TO DVI Conversion
which I will be updating to completion over the next several days.

The reason I call this the easiest so far is that it involves No Soldering, Minimal Technical Skill, and Can Reasonably be done in 1 Hour.


When I look back at my older mods which involved total neck disassembly, 50+ solder points, and hours upon hours of time, I can not believe how much easier this is.  Not only is it easier, it is cheaper, ore stable, and overall just better.  If you are interested in doing the 17" version  of this iMac mod then take it from someone who has already made every mistake you could possibly make - USE THIS METHOD!

For Now I am only taking this to the level of getting a DVI compatible connection in the base with power. The only thing you need to do is plug something into the DVI receptacle.  If that is an internal mini itx, ecx, or external mac mini, or windows atx tower - that is your choice.  I will likely demonstrate use of the ECX board later on.

To be honest the only difference is in one <$5 part and that is the DVI-I connector header
  Specifically I used a  MOLEX PN 74320-4004

FRONT

TOP

BOTTOM

NOT THESE BIG PINS
Now this exact one is likely not needed.  The important this is that you need a DVI-D or DVI-I with these small pins as opposed to the usual connectors that use large pins:

I would recommend a right angle connector (you can work outside the dome then fit a right angle connector through the hole on top without having to remove all the pins).

Also, female is easier and I believe gives more connection options, but male can be used if you remember to alter the pinout and can find a connector with these small pins.

The remarkable thing about this connector is that it could not be designed better for the iMac G4s female pins.  Not only are the male pins on this connector identical to the ones on the iMac G4 motherboard shape, width, and length, but they are spaced well enough apart to prevent and disturbance between pins.  All you have to do is take the iMacs video connector and break apart its housing, freeing the individual pins/wires.  Easily push the iMacs wires onto the correct pins (12 TMDS pins, 2 control pins).  Then add an extra ground and make 1 split cable with a resistor (5V/hot plug).  Hook up 6 aligator wires to voltages (2 Ground, 3 5V, 1 12V) and turn it on.

Of note, I have tweaked the inverter pinout somewhat in the tutorial as well.  This change may be specific to this build.
I love that it lists the display as "iMac"
Enjoy and I look forward to hearing stories of rejuvinated iMac G4's! Thanks for reading.

23 comments:

  1. Hi,
    Does this mod apply to the 17" 1.25ghz iMac? Mine "die" a month ago and I was wondering if I could do this.

    ReplyDelete
  2. Mac, it's the same thing, except for some reason they changed some wire colors between the 2 necks. I will be doing a step by step once my 20" mod is complete. But if you want to get started, it's quite easy to make the changes. Use the 1/1.25 ghz pinout seen in this post:
    http://dremmeljunkie.blogspot.com/2011/03/two-17-imac-pt:
    For the Black LCD Cable:
    Pins 1,2, and 3 - use Brown wire instead of Red
    Pins 9,10, and 11 - use Blue wire instead of Orange
    Pins 17,18, and 19 - use Green wire instead of Blue
    Pins 22, 23, and 24 - use Red wire instead of Green
    For the Grey LCD Cable:
    White and Black are reversed
    Pin #6 is black, while Pin #7 is white
    blue and purple are switched. blue is now connected to ground not to 5v. While purple is now connected to 5v not ground. Everything else is unchanged.

    ReplyDelete
  3. I guess it would be possible to use an extender and use this as an external monitor? Or would the added cable length compromise the signal so much that there would be any delay/degrade the image quality? :)

    Thanks for a great site!

    ReplyDelete
  4. The wires in the neck are essentially DVI. There are about 2 feet of cabling in the LCD and neck, the maximum DVI length without a signal booster is stated to be around 16 feet, so I would try to keep any extension less than 14 feet. Though as the resolution is only 1440:900, I would bet you could do over 25 feet without any noticeable signal loss.

    ReplyDelete
  5. First of all, I would like to thank you for taking the time to document your projects. I've been scowering your blog for the last week or so and have decided to take the plunge!

    I love the flower pot design, it is truely a fun and functionaly masterpiece, and am glad we now have the oppurtunity to take advantage of current technologies to bring it back to life.

    Anyway this is going to be rather long so I appologize in advance. I managed to pick up a 17'' imac g4 off the CL today for $50 (Delivered!) as pictured in my avatar. The 'only' problem it has is that the screen is blacked out (due to a dead inverter I assume). Im thinking this might actually not matter to much in my situation. Anywho after scheming and weighing the pros and cons this is what i will be attempting to do.

    1. Mac mini to TV through DVI (as HTCP / Server)
    2. Wireless VGA to DVI thought something like this:

    http://www.amazon.com/s?ie=UTF8&rh=n%3A172282%2Ck%3Awireless%20dvi&page=1

    This does pose some problems tho;

    1. G4 does not support VGA, will have to 'Jury Rig' DVI as per "easiest mod ever"
    2. I dont even have a working screen lol.

    I'll post my questions in another box to avoid boredom.

    ReplyDelete
  6. I see that the imac has some kind of "l Box l" thing. I see that this means mini DVI. im thinking / hoping it would be possible to Down Convert somehow..

    If that is not possible I'll have to open er up and Jury Rig the easiest mod ever, no biggie.

    BUT

    Seeing as how the Inverter is dead anyway.. cant I just throw the black part from from macbook pro or something like that.. or use Mac Book Pro's Inverter which would be supported by the wireless DVI dongle ?

    I think this would be awesome, you would be able to boot up in old school mode.. then switch to Lion whenever you want (imac in spanning mode).

    forgive my ingorance if this is some crazy idea. im not 'much' of a hard core techy. I do have an imagination and deterimation for simplicity.

    Any advice you could give would be greatly appreciated.

    ReplyDelete
  7. Dunky, To be honest, I'm not exactly sure what you are asking. You wrote about a MacBook pro, a Mac mini, a TV, and a wireless VGA dongle. I'm really not sure what you are trying to connect to the iMacs screen and if you want it external or internal. But, a few notes. If your iMac g4s inverter is not working you will need to replace it. You can not use the signals source as the inverter. The inverter controls the backlights on the iMacs screen. Your image will be dark without this no matter what you source you use. Also the mini DVI is for video out only. There is no video in on the g4. You are correct that the iMacs LCD uses a DVI digital signal only. Any analog signals such as VGA will need to be actively unconverted. This may require an expensive powered device. Hope this helps

    ReplyDelete
  8. I wasn't being totally clear.

    After much debate and research, I've just decided to gut the iMac and shove a new Mac mini inside, I'll have to jury rig the monitor but no big deal.

    If you look at the cost of the tony86x build its really not that much more expensive, and your stuck with snugly box, have to upgrade to lion and by the looks of it alot of users are having great difficulty.

    The Mac mini runs at 599, which I can get at a discounted rate.. And if it fits .. I'm sure some eBayer will pick it up.. If it well.. It's a georgous piece of hardware anyway.

    Appreciate all the work youve done, and I'll couldn't do it without ur pinout, and the touchscreen is awesome! But this'd seems like the best option for a noob. Although it has encouraged me to get into electronics and perhaps I'll build a pro when I'm a bit more proficient.

    ReplyDelete
  9. Ever since you've started this i've been wanting to turn a G4 into an external monitor.
    Somehow I kind of forgot this until last sunday, there was a 17" G4 for sale in the neighbourhood for a steal.
    Picked it up and ended on your blog and youtube-clips again to read all your work.

    Somehow I missed this particular post but i'm glad I thoroughly read everything by date.
    First going to look for all the 'ingredients' then start doing it asap!

    Thanks!

    ReplyDelete
  10. Just to make things sure, do you have a picture of this, because i'm not certain what you mean by this. (Might be the language barrier):

    "Then add an extra ground and make 1 split cable with a resistor (5V/hot plug)."

    Especially the resistor (5v/hot plug)-part. What kind of resistor does it have to be? How many ohms?

    ReplyDelete
  11. Will the resistor is a 1Kohm resistor. I have a detailed description with pictures on this post:
    http://www.dremeljunkie.com/2011/08/guide-step-by-step-17-imac-g4-tmds-to.html

    Good Luck, JB

    ReplyDelete
  12. Is tmds related to hdmi and if so could i do the same as this except with hdmi and not dvi and if its possible could i use this guide with a 15' imac g4.

    ReplyDelete
    Replies
    1. Oh and i forgot to say i want to use with the new mac mini so i wont need an adapter for dvi

      Delete
    2. Yes TMDS is the type of signaling used by HDMI and thus you could use an HDMI cable or connector. That said, the DVI connector that I talk about is very highly recommended. Its possible that a similar HDMI connector exists, with perfectly sized pins exists, but I'm not sure. I just added a refreshed "Mod Advice" Post that explains why this connector makes it so much easier. Good luck and keep me updated.

      Delete
  13. hello i have problem I connected everything and my monitor shine but nothing display on my iMac monitor i use svga to dvi adaptor because my laptop don't have dvi slot ;/

    ReplyDelete
    Replies
    1. The signal is digital only. While DVI can have a concurrent analog signal, this mod does not use the analog area, because there is no analog signal from this monitor. So when you connect a DVI to VGA adapter, you are connecting it to empty ports. You either need to use a digital source or an active converter that converts analog to digital.

      Delete
  14. The above post seems rather rushed.

    Can you give me more of a step-by-step instructions on this "easier" method

    ReplyDelete
  15. I'm confused by this comment. I made this post immediately after using the DVI connector for the first time. I was able to get a stable signal in an hour vs 6 hours of soldering work. This post is just about the DVI connector. If you are looking for more detailed post and more of a "step by step" you need look no further that he first two lines which say. For more details see: [hyperlinks to a post called "Step by Step 17" Guide"].

    Don't misinterpret the easiest method so far to mean that this mod is easy, it's not. But the DVI connector certainly goes a long way in terms of reducing the time and soldering skill required to get this working.

    ReplyDelete
  16. I just got the DVI connector and realized I have a 15 inch iMac.
    Will this work for 15 iMac G4?
    Do you know how different the wire colors are?

    ReplyDelete
  17. I successfully did this build with immense help from your guide, thank you so much. Recently my backlight for my 1.25GHz neck iMac G4 stopped working, but the data still works because I can see the screen with the right amount of light shone on it. I suspect the inverter died, when I made the power connections to my Mini ATX power supply I noticed the screen was a little hot, but I didn't think anything of it, maybe that was telling me I was supplying too much power? I used the 1K resistors with a .25V tolerance, do I need a .5V tolerance?

    I have had an old white Macbook come into my possession, I'm not sure from which year but it looks like from 2005 or 2007 before the round white MacBooks. I was wondering if you think I could use the inverter from this macbook and replace the dead one in my iMac G4 build?

    ReplyDelete