GUIDE: Step by Step 17" iMac G4 TMDS to DVI Conversion - 800mhz Neck Completed, 1/1.25 Ghz - In Progress

Mac Mini identifying monitor as "iMac"

This is a step-by-step detailing the process of converting a 17" iMac G4 to a useable LCD with a video cable that terminates with a DVI connector in the base.  I may go further and complete this as an updated all-in-one using an ECX board - but for now I will focus on the video connector.  Please note that I am not starting from a complete machine.  I have several necks, empty domes/bases, and LCDs that I have obtained through various sources as individual parts.  So my tutorial will not focus on the general disassembly and reassembly, but on the wiring and powering of the LCD.


For those who have not followed my blog, please be aware that there are two versions of the wires in the 17" Mac G4 (Two different necks).  One version is for the 800mhz iMac, the other is for either the 1 or 1.25ghz iMac.  If you use the wrong one - it will not work.


Sorry for the delay in the 1/1.25Ghz step-by-step, there is only a slight variation, just use the correct pinout.  I have been working on the 20" version.  Once this is completed, I will turn my attention to this.


Note: This is a financial investment, the parts that go into this are used and in some cases 10 years old.  Mistakes or even bad luck may result in no image or even permanent damage to components.  So know what you are getting into.  I can not vouch for the long term stability of this mod.  Although this mod is solder-less and simplified, obviously soldered, insulated connections are likely to be more stable.  Even though I have simplified the process, this is still an advanced mod.  Be cautious when handling live connections which (in the case of the inverter to backlight) can be several thousand volts.  So if you're still ready, lets get started:


I. PARTS LIST
These are the parts that I used or very common alternatives - MANY other variations are unquestionably possible, but I can not guarantee something I did not see work personally.  In some cases I will list where I purchased it from - this is in no way an endorsement of any particular merchant or sales site - just a statement of how I acquired it.


A) iMac G4 17" and components

1. Monitor Housing - 2 pieces (front and back) contains LCD and inverter



17" Inverter

2. Neck - while structurally the same the neck's of the 800mhz model has different colored wires than he 1ghz and 1.25ghz models.  As both pinouts are available it does not matter which you choose.



Faraday Cage

3. Dome - contains computer components (none of which are used), A white plastic overlay, a metal faraday cage (the metallic inner part of the dome), the bottom of the dome, and a circular tray for the bottom.

The hardest to buy, you need a working LCD and Inverter for this mod.  As broken computers may or may not have functioning LCDs - its a tough choice. 

Please try not to tear apart working machines - there are fewer and fewer of these available.  Ebay is littered with hundreds of broken machines and parts that can be recycled.  If the machine you buy is "dirty" - you can buy a new plastic outer housing for the dome.  If the screen or inverter doesn't work, they can also be found easily on ebay.

B) A Power Source - to power both inverter and LCD screen

Pico Power Supply

Any power source that has at least a DC: 12V and a 5V line will work, however addition of a 3.3V line actually matches up closer with the panels specs.  Despite this, I have not seen any problem with using only 12V and 5V.  As this makes everything more uniform and simpler, I am focusing on using these voltages via a standard molex connector.  Alternatives include any atx power supply with a molex. As there is limited space, you should choose a small power source like a pico power supply which is a DC-DC power source that uses an external power brick, but any atx power supply will work.  If you use an atx power supply you will have to "jump" it to get it to turn on without a motherboard.  This can be done by inserting a paper clip or wire between pins 14 and 15.  Simply put - grounding pin 14 turns on the power supply.

Rocker Switch

While this alone works you should think about putting some wire with an on/off switch between these.  Do not use a momentary switch, you need a real on/off (such as a rocker or toggle switch).

logicsupply.com has a nice selection of Pico Power Supplies, I'd probably recommend at least 120Watts.  Make sure you buy a DC-AC power brick as well.

Another option is a DC to molex power supply this gives the necessary 12V and 5V line and also connects to a regular AC plug.  This is what I am using for now.

Whatever you choose, it must simply have a working 4 pin molex plug.  My tutorial is based around using a working molex in combination with a molex splitter.  Cutting off the 2 female connectors and stripping the ends will give you 2 of each of these: 12V(Yellow), 5V(Red), Ground(Black).  Available from newegg.com.

Molex Splitter

Another possibility is using the native iMac G4 power supply.  As it has 3.3V, 5V, 12V, and Ground.  I do not have a working power supply and I therefore can not test it.  I also do not know if the native power supply can be easily "jumped" or not (though I would be surprised if it couldn't)

C) Accessories and Cables

LVDS Cable

    1.  Extra Small Wires and Pins. Optional but recommended.  You can use the extra wires in the iMac itself such as the fan or speaker cable, but using the proper pins is much easier.  One way is to buy LVDS cables (on ebay) and one source I've found is a company called njytouch on ebay.  They sell a standard 30 pin LVDS cable with JAE connector. However, the best source of iMac G4 wires is obviously an iMac G4 .. so buying an extra neck as a source wires and pins may come in useful especially if you make a mistake.  These are always  available on ebay and it does have to come from the same size iMac.  Of note, I used 3 small wires with pins from a 15" iMac G4 neck. (The neck does not have to be opened, I just cut off the last few inches).  I also used a wire from the LVDS cable pictured above.  Again you do not need either of these in particular, but you do need 4 small gauge wires (about the same gauge as the cables in the iMacs gray lcd wire).  The wires do not have to be any longer than 10cm.  Ideally 3 of the wires should have pins similar to the termination pins on the other cables, through this is not a requirement.  If you have a broken monitor, the cables from this may be enough.  Or you cab search for used LVDS cables on ebay, and this should give you enough options.

    2.  Torx Screw driver kit or set, Philips screwdriver, Small Flat head screwdriver or mini screwdriver set.

    3.  Soldering iron and solder (not required but can be useful for making some connections more secure or for repairs).

    4.  A safety pin - for removing pins from connectors

    5.  Electrical Tape and/or heat shrink

Multimeter

    6.  A multimeter with continuity setting.  This is useful in checking the integrity of the connection especially if you are not getting an image

    7.  Alligator wires (at least 7).

A Stripped, Cut Cable

    8.  A Cable or connector for splicing.  This must be a TMDS cable such as DVI-D and HDMI.   Alternatives include:

          a) Cut DVI/HDMI cable: This is easy to obtain and using a mutimeter, it is easy to find out which wires corresponds to which pin.  After striping you will find the TMDS control wires (Clock, Data, Hot Plug, 5V) as well as 4 groups of wires that are further shielded.  These are the TMDS signal cables.  Each one of these has a positive wire, negative wire, and ground.  Just remember when using a DVI cable the connector is MALE and this does not correlate directly to the standard diagrams and pin numbers which are based on a female connector.

DVI connectors (Female)

               b) A DVI connector (with small pins) - allows the pins to interact directly onto the connector.  The shorter the cable and less connections and changes in resistance, the better the quality of the connection.  Also allows use of female connector (pin out is easier to follow).  Likely any small pin DVI-D or DVI-I connector will work, but I used this one:

http://www.ebay.com/itm/2-HDMI-DISPAYPORT-DVI-Connector-/300567646450?pt=LH_DefaultDomain_0&hash=item45fb3a50f2#ht_1180wt_1413

from a company called leetechtool which sells 2 connectors for $5 ($2 shipping).  Opentip.com also has a similar appearing DVI connector though I can not confirm it is exactly the same.

I highly recommend this DVI connector it greatly simplifies the process and is much more stable.  My guide is based on this connector.

    9. Three 1-Kohm resistors.  Interestingly, you may only need 2 (One pin on my inverter pinout may be superfluous), but until I have fully verified this, I would have 3 ready.  Since they are $0.98 for 10, the extra one won't be a big waste.  I used these from parts express via amazon.

  10. Wire cutters, strippers, and a scissor.
           
II. Disassembly

Courtesy of mrtotes

          - I have decided to skip a lengthy tutorial on disassembly.  Numerous tutorials exist on line for this.  Changing the hard drive requires near total disassembly.
Here is one tutorial for the hard drive:
 http://www.xlr8yourmac.com/systems/iMac_g4/imacg4_takeapart.html
And one teardown:
 http://68kmla.org/forums/viewtopic.php?f=13&t=13550

Briefly:
        - Using the torx screwdrivers open up the iMac's dome and remove the drive caddy which includes the hard drive and optical drive and set it to the side.  Physical removal of the fan, internal speaker, motherboard and power supply are not required and can either be done or left alone depending on what you plan to do with the iMac's base.

Inverter plug unhooked

Video cable unplugged

        -  Removal and isolation of 2 cables: the inverter and LCD is required.
Disconnect all cables.  I would recommend at least removing the drive caddy.  The rest is up to you.

Remove the black cover from the video cable with a flat head screwdriver and gently remove it from the motherboard.

Also remove the large plug which contains the cable labelled inverter

Using a safety pin lift up the black tabs

on the large inverter connector.  As the tabs are lifted gently pull each individual inverter pin free.

For the iMacs LCD cable you must first remove the metal casing using a flat head screwdriver or x-acto knife.

- First pry open the top

- Then the side

- And then the metal cover should bend back and snap off

Pry open the top

Then the side

Peel Back and Snap Off

Exposed LCD Connecter

When the black is fully exposed you will again see little plastic tabs on the side.  Using a safety pin lift these tabs and push them down (its ok if they come off entirely).  You want to see the exposed metal from the pins where the tabs used to be.

When all tabs are done, VERY GENTLY pull the individual wires and pins free.

You may need to again use your safety pin to press down on the pin in the area where the tab used to be in order to help free it from the black connector.

NOTE: THE ENTIRE EASE OF THIS MOD IS DEPENDENT ON THE PRESERVATION OF THE WIRES WITH THEIR INDIVIDUAL PINS.  RIPING OFF EVEN ONE PIN FROM THE WIRE MAKES THIS MUCH MORE DIFFICULT.  USE MINIMAL FORCE AND TAKE YOUR TIME.

III. The Inverter
  - I recommend hooking up and verifying the inverter first.  This way you know right away if you need to replace your inverter.

  A)The pinouts

To the left are the pinouts for the inverters.  I had thought that  the 1/1.25ghz iMac used a neck that had an Orange Dimming wire in the inverter while the 800mhz had the off white.  However, on the neck I used here which was clearly an 800mhz neck, there was an orange dimmer wire.  While this does not matter (as both are left floating), it does mean that this is not a valid means of telling the different models apart.

In addition, while I had thought the purple was the on/off, it may actually be green or red.  The purple may not need to be connected at all.  I am still investigating this.  For now I would recommend proceeding with the pinout as shown and as described below.

B) The molex splitter

1.  Take your molex splitter and cut off the two female connectors.

2  Strip the ends off:
      - 1 Yellow (12V)
      - 2 Red (5V)
      - 2 Black (Ground)
   2 Blacks and 1 Yellow can remain with no wire exposed

Molex Splitter To AC Power Source
(Note: I removed the extra black pin
but this is not necessary)

3. Connect the molex male end to the female molex of your power source which should be OFF

4.  Place Alligator Wires on
- Attach Yellow Alligator wire to one yellow molex wire (Note: I have two attached in the pic but you only need one)

- Attach Black Alligator wire to one black molex wire

- Attach Two Red Alligator wires to red molex wires (but on 1 wire attach sideways leaving end exposed for a second wire) as seen in picture.

- Attach one Green Alligator wire to end of the red molex wire. (Using Green simply helps telling the wires apart).

Alligator Wires to Molex (yellow is out of frame)

5. Take 2 1 Kohm resistors and twist one end onto the PURPLE and GREEN wires of the inverter cable

Resistors wrapped around Green and Purple pins

 

 6. Connect your alligator wires to the inverter pins

- Connect Yellow to Blue pin

- Connect either Red to Red

- Connect the other Red to the resistor wrapper around the Purple pin

- Connect Green to the resistor wrapped around the Green pin

- Connect Black to the Black pin

- Orange or White (depending on neck) inverter wire is not connected and left floating.

7. Turn on your power source.  The backlights should come on as seen below.  If so, turn off the power and continue on.  If not check your connections.

The backlights on

IV: The LCD Cable
- Be aware this will split into two different parts, one for the 800mhz iMac and one for the 1/1.25ghz.  If you do not know which one you have, see my two necks post.  The easiest (without disassembly of LCD) is to see if your black LCD cable contains a BROWN or ORANGE cable.  These will split into a red, green, black.  BROWN = 1/1.25ghz and ORANGE = 800mhz.


1. Grab your DVI connector and find a good DVI/TMDS pinout for reference in you get confused.  The one I have pictured below is courtesy of Tom's Hardware.   Just remember the numbers reflect a FEMALE DVI connector.  This is a digital only signal, so we will be using the areas highlighted a TMDS and also the control areas (labeled plug and play).  A TMDS data source actually contains 3 parts - POSITIVE, NEGATIVE, and GROUND.  DVI allows up to 7 of these (0,1,2,3,4, and Clock).  The iMac's LCD requires 4 (0,1,2, and Clock).  These correspond to the 4 colored wires that are in the iMac's black LCD cable.  And each one of these has 3 wires inside a red, green, and black.  This corresponds to the positive, negative, and ground signals respectively.

Courtesy of Tom's Hardware

2. Orient Yourself

FEMALE DVI CONNECTOR PIN NUMBERS

There are 3 Rows of 8 holes

The picture on the right is the front view
- The Top is recognizable as the "Analog Area" should be on the right when looking straight on.
- In addition, the connector is a parallelogram and the longer side is on top
- They are numbered left to right and the middle 2 rows are not used at all
- The Red boxes correspond to the pins for the TMDS signals (the pins in the iMac's black wire)
- The Green boxes correspond to the pins for the control (the pins in the iMac's gray wire)

Connector from top

As this is a right angle connector there are right angle pins visible on the top of the connector.  This then terminates in the male pins we will be using on the bottom.  See TOP VIEW

In the BOTTOM view below you can see that the top row pins (1-8) actually become the bottom row when looking at the pins from this angle.

The "Analog Area" will always be at the end.  So the closest pins to this area will be 8, 16, and 24 in the top, middle, and bottom rows respectively.

Bottom View of connector with"Free" iMac LCD cable.

LCD Cable with black heat shrink removed

3. Separate the Black and Gray iMac LCD wires

-  This gives you much more room to work with

-  Using a small scissor or wire clippers cut a small nick into the black heat shrink which envelopes both wires.

-  With your hands pull apart the sides of the heatshrik next to your cut.  It should pull apart easily.

-  Underneath is a piece of gray cloth tape, unravel this until the wires come apart



THIS GUIDE NOW DIVIDES


THE RED BELOW WILL BE FOR THE 17" iMAC G4 - 800Mhz VERSION / NECK


THE BLUE (WHICH IS PENDING) WILL BE FOR THE iMAC G4 1 or 1.25 Ghz VERSION / NECK


The 800mhz Neck:


4. Review this pinout for reference.  This tells you which color wire and female pin (left column) will be pushed into which male pin on the DVI connector (right column).  In the middle is a description of the wires function.

800 mhz 17" iMac G4 pinout

5.  The TMDS Signal - The Black LCD Cable


A) THE RED WIRE

- Locate the RED wire from the black cable and identify the 3 wires that come from this cable.  The Green, Red, and Black.

Red Wire - Connecting Data Cable #2 (Pins 1, 2, and 3)

- This is the Data #2 Cable
-  Of note is that the small green cables will always be negative and the small red cables positive.  The Black is the shield or ground.
- Locate Pins: 1, 2, and 3 on the connector
- With the actual DVI part face down, find the pin furthest away from the "Analog Area" and on the row closest/top row.  This is PIN #1


i) Take your Red to Green wire
- Using your fingers position the female pin with the "seam" facing either up or down (towards the Front to back of the connector).
- DO NOT PUSH IT IN SIDEWAYS.
- Using very gentle force slide the Green wire on to PIN #1.  You can press until to reach the plastic of the connector.
-  Do not push against significant resistance.  The pin should fit easily and securely.
- Once in place it should hold fairly firmly.


ii) Take your Red to Red wire and push it into position #2 next to the green wire.


iii) Take your Red to Black/Shield and push it into position #3 next to the red wire.

B) The Orange Wire
- The is Data Cable #1
- Locate Pins 9, 10, and 11
- These are the middle row pins in the same column as the Red wire you just placed.


i) In the middle row, right in front of the Red to Green pin, furthest from the analog area, place your Orange to Green Pin - Position #9


ii) Next to this in Position #10 (in front of the Red to Red), place your Orange to Red pin.


iii) Finally in Position #11 (in front of the Red Shield/Ground), push the Orange Shield/Ground into place.

Orange Cables Pins Directly in Front of Red Cables Pins

RED, ORANGE, and BLUE Connected

C) The Blue Wire


- This is Data Cable #0
- Locate Pins 17, 18, and 19
- These are the top row pins (bottom view) just above the orange pins you just placed.

i) In the top row (the blue square), right in front of the Orange to Green pin, furthest from the analog area, place your Blue to Green Pin - Position #17

ii) Next to this in Position #18 (in front of the Orange to Red), place your Blue to Red pin.

iii) Finally in Position #19 (in front of the Orange Shield/Ground), push the Blue Shield/Ground into place.

D) The Green Wire

- This is the Data Cable - Clock

The Green Wire (Notice how its the mirror image)
Small Green Always on the outside
Shield/Black in the Center

- Locate the Pins #22, 23, and 24

- These pins are the last 3 in the row, closest to the Analog Area.  They are in the same row as the pins from the BLUE WIRE you just placed.  The row closest to the DVI interface.

-  NOTE THAT THE ORDER OF PINS IS DIFFERENT FOR THIS WIRE

          PREVIOUSLY ALL PINS WENT GREEN, RED, SHIELD FOR THE GREEN IT IS REVERSED.  IT GOES SHIELD, RED, GREEN

          THINK OF IT AS THIS, GREEN IS ALWAYS ON THE OUTSIDE, SHIELD ON THE INSIDE.

          SO FOR THIS WIRE WE WILL PLACE THEM GOING RIGHT TO LEFT

i) In the top row, same row as the Blue Wire, closest to the analog area (the last pin in the row), place your Green to Green Pin - Position #24

ii) Next to this in Position (going right to left) #23 (same row as Blue), place your Green to Red pin.

iii) Finally in Position #22 (same row as Blue), push the Green Shield/Ground into place.

Completed Top View

Completed Front View
Green Wire's Pins in Foreground on Left
Blue Wire's Pins in Foreground on Right

6.  THE POWER SOURCE - THE GRAY LCD CABLE
- Of the Nine Colored Wires inside the Gray LCD Cable, only 3 of them actually connect to the DVI connector (Red, White and Black).  The other 6 connect to either 5V or Ground


A) The 5V Cables
-  Grab your Gray LCD Cable
-  Separate Out the Blue, Orange, and Yellow
-  Take a RED alligator Wire and place these 3 pins securely within its teeth

BLUE, ORANGE, and YELLOW to 5V

B) The Grounds

- Do the exact same thing for the 3 Grounds:

- Separate out the Gray, Purple, and Green Wires from the Gray LCD Cable

- Take a Black alligator Wire and place these 3 pins securely within its teeth

On Left: BLACK ALLIGATOR (Purple, Grey, Green)
On Right: RED ALLIGATOR (Yellow, Blue, Orange)

C) Connect to Power Source

- Looking Back at your power source, one 5V RED MOLEX wire is connected to 2 Alligators, the other to 1 Alligator.  At the 1 Alligator Wire add the RED Alligator from the Gray LCD cable.  Now both should have 2.

- For the Ground connect it to the unused Black Molex Wire.  The other black cable should be attached to an alligator wire going to the Black Pin/Wire on the Inverter Cable.

7. THE TMDS CONTROL WIRES (VEDID, GROUND, and HOT PLUG)
- These 3 Wires will Plug into Pins 14, 15, and 16, respectively.  This is the Middle Row of Pins directly behind the 3 pins from the Green Wire on the Black LCD Cable.
- Only 3 wires from the iMacs LCD cable remain unused.
- However there are a Total of 5 TMDS Control Pins, only 3 come from the iMac's wires, for the 3 listed above we will need extra small gauge wire, similar to the wires on the iMac's Gray LCD cable.
- For this part really 4 small gauge (about 24 - 28) wires are needed.  3 of these should preferably include pins that can plug into the DVI connector and be somewhat long (about 10cm).  1 other can be shorter and does not need the pins.
- Note: This is probably the trickiest part.

Cables from the LCD connector of a 15" iMac G4

A) Prepare your extra wires


Your options for this are extensive.  These 4 wires carry either voltages or ground (not sensitive display signals, as such they don't need to be "perfect" they just need to make a connection.


Options again include:


1) Extra LVDS or small gauge wires from anything (i.e. old monitors, computer fans, stripped HDMI/DVI cable etc.)
2) LVDS cables from nyjtouch (see parts list)
3) Cables from an extra iMac G4 neck of any size (the ones in the video cable).
*4) Extra wires/pins from this iMac G4's Gray LCD cable


*Note that #4 is new and requires no extra equipment.

For #4: Peel back the Gray LCD cable's Plastic and Shielding about 16cm.  Isolate the Ground Wires: PURPLE, GREEN, and GRAY. (You can use the 5V wires as well, but I would feel safer cutting the grounds).  Cut these three wires at about 10 - 12cm.  Make sure you leave enough wire remaining so that it can be easily stripped.

*Note these pics reflect an extra damaged iMac cable I had.  I had this idea too late for this mod, but I will use this method for the 17" 1/1.25 Ghz Guide.

Plastic and Shielding Peeled Back

Take the now cut ends of the PURPLE, GREEN, and GRAY wires in the Gray LCD cable and strip the last few centimeters of each of these wires so that each now has exposed wire at the end.  Twist these 3 wires together.  You can now hook this up to an alligator wire or a different wire and hook it back up to the Molex's Black/ground wire.

Because you have 3 wires and need 4, you can cut off 1/3 of one of these wires (not the pin end) or use an extra cable such as the iMac's speaker or fan wires or an LVDS cable with a male pin on the end.  So you should have 3 long wires with the pins on the end and 1 short wire, with either a male or no pin on the end. 

Note: I used 1 cable from an LVDS cable and 3 from the neck of an iMac G4 15".
If you need just one, you will be fine with only the extra cables from an iMac neck, which makes this part easier and more stable.

The 4 wires with pins on

Take your cables and expose about 10 - 12 cm and cut off 3 wires (preferably with female pins still attached), and 1 more wire with either a male pin or no pin at all (can cut off female pin).


B) The 1st Extra Wire - TMDS CONTROL GROUND


i) Take one wire with a pin on it (preferably) - I USED A GREEN COLORED WIRE - but it does not matter what color you use, just remember what it is.  Strip the non-pin end of the wire (2 - 3cm)


*I would strongly recommend using a wire that has the proper pin on it even if it means using the iMac's own ground wires.  So if using your own LVDS cable, make sure the pin fits appropriately.  This will be far more stable.


- I am going to recommend a small wire stripper, but to be honest, I usually use (against all dental recommendations) the bite and pull method.

One wire with pin on one end, stripped on other

ii) Wrap the stripped end around one of the Black Alligator Clips that (the other end) connects to the Black Molex Wire (The Ground).  I chose the wire that holds the Green, Grey, and Purple Grounds from the Gray LCD cable.  You can also use the other ground / alligator wire that connects the inverter's ground cable to the other Black Molex / Ground.  It does not matter.

Alligator wire with "Extra" Green Wire wrapped around

iii) Place the Pin from this Wire into Position #15 on your DVI Connector
- This is in the Middle Row, the last pin from the end (by the Analog Area)
- This pin gets placed directly behind the RED pin from the GREEN wire of the BLACK LCD cable (the last colored wire we placed).

Ground Wire to DVI Connector #15

C) The Second and Third Extra Wires - TMDS Control Voltage (VEDID) and Hot Plug


Some quick background: 
- The DVI source (the computer) actually has a pin that sends a 3.3V signal to the LCD that tells it to turn on.  This is how the image turns off when the computer tells the monitor to sleep.  In addition, the LCD itself sends a low voltage in THE OTHER DIRECTION, back to the DVI source (the computer).  This lets the computer know that there is something connected to this port.


- The voltage sent from computer to LCD (the LCD's on/off) is called the VEDID and this is Pin #14 on the DVI and connects to the Red (looks somewhat "Hot Pink") wire in the Gray LCD cable where its transmitted to the LCD itself.


- The voltage sent from the LCD to the computer is called the "HOT PLUG DETECT".  This signal is supposed to come from the LCD and plug into Pin #16 on the DVI Connector.  However, this monitor was  designed to always be connected.  So, the iMac's LCD does not have a wire that corresponds to the Hot Plug Detect.  To "fool" the computer we can give its own signal right back to itself.  However, we need to lower the voltage, which we do by adding a 1-Kohm resistor.

3 Extra Wires and Resistor

i) Get Prepared


     a) Take Your "2nd Extra Wire" with Female Pin,  cut and strip the end, (again about 10 - 15cm, but strip off a large segment of the end without the pin 3 - 4cm)
- Again I used a wire from my extra 15" iMac neck, with a female pin, but you can use whatever you chose.  My wire is recognizable as the Red with Black Stripe.  This wire will be the VEDID and will connect to Pin #14 on the DVI Connector


    b) Take Your "3rd Extra Wire" with Female Pin, repeat as above.  Although you don't need to strip off quite as much (2cm will do).  My wire is recognizable as an Orange with Blue Stripe.  This wire will be the HOT PLUG DETECT and will connect to Pin #16 on the DVI Connector.


    c) You need one more wire with either a male pin or no pin at all.  I took this wire from my LVDS cable.  You can take a male pin from the iMac as well.  But having no pin and simply being stripped on both ends will work fine.  This wire can be shorter, 5 - 7cm will do.


    d) Your final 1 Kohm resistor


ii) Create Your HOT PLUG and VEDID

Extra wire wrapped around 1st part of strip

- So you should have 3 wires


    1) VEDID - Wire with (preferably) female pin at one end and a long section of stripped/exposed wire at the other end - MINE IS RED WITH BLACK STRIPE


    2) HOT PLUG - Wire with (preferably) female pin at one end and a short section of stripped/exposed wire at the other end - MINE IS ORANGE WITH BLUE STRIPE


    3) EXTRA WIRE - Short Wire with either male pin or short strip/exposed wire at one end and short strip/exposed wire at the other end. MINE IS A PLAIN RED WIRE


-Wrap the stripped extra wire around the first part of the VEDID's stripped wire, but leave at least a few cm of stripped wire from the VEDID sticking out as seen in the picture.


- Wrap the 2nd part of the VEDID's strip around the 1 Kohm Resistor


- Wrap the Stripped end of the Hot Plug Cable (ORANGE WITH BLUE STRIPE) around the other end of the resistor.

Completed VEDID and HOT PLUG Cable

Again, what you see above is simply a split.  The voltage goes from the computer through the DVI connector to the VEDID (Red with Black Stripe Wire via Pin#14).  It then splits into two.  One signal sends the original 3.3V via the "Plain Red Wire" to the Red/Hot Pink wire of the Gray LCD cable, which carries this to the LCD to turn it on.  The second split sends the 3.3V from the VEDID to the 1Kohm Resistor (which reduces the voltage) and connects back to the DVI connector via the HOT PLUG (Orange with Blue Stripe via Pin #16).  Thus, going through the DVI connector to "fool" the source.

Resistor wrapped in Electrical Tape

Completed Cable

- Wrap the Resistor and exposed splice with electrical tape.

VEDID (#14) and HOT PLUG (#16) surround
GROUND (#15)

iii) Plug the VEDID to Pin #14
- This pin is in the middle row, next to the the Ground wire that was just placed.
-  It is 3 pins from the "Analog Area" at the end
- When looking at the connector from the front (DVI interface facing you), this pin is directly behind the the Black/Shield from the Green Wire of the the Black LCD Cable.


iv) Plug the HOT PLUG DETECT to Pin #16

- This pin is in the middle row, on the other side of the Ground wire that was just placed.

-  It is the last pin of the row and is next to the "Analog Area" at the end

- When looking at the connector from the front (DVI interface facing you), this pin is directly behind the the Green from the Green Wire of the the Black LCD Cable.

Note:

*If you use a wire without female pins (ex. DVI/HDMI wires) or wires with female pins that are much too large you need to strip the DVI connecting end of the wire.  Take your stripped end and wrap it around the pins (#14 and 16) several times and secure it with a small piece of electrical tape.

*If your female pin is just slightly too large (ex. Some LVDS wires) you can take a pair of pliers and make the opening somewhat smaller so that it holds securely to the DVI's male pin without touching adjacent pins.


v) Connect to iMac's LCD Cable
- You should have 2 of the 3 ends plugged into the DVI.  This leaves the one remaining short "extra cable".  I've been using the plain Red wire with a male pin.

VEDID (Pin#14) to iMac's Gray LCD Cable - Red Wire

- Take this end (if you used a cable with a male pin) and plug this male pin into the female pin on the Red (somewhat Hot Pink appearing) wire from the iMac G4's Gray LCD cable.


- There should only be 3 wires left unhooked on the Gray cable: White, Black, and Red(Hot Pink).  So, it should be easy to identify.


- If you don't have a male pin, it is no big deal.  Simply strip a few cm off the end of your "extra wire", where the male pin should be, and wrap this around the female pin from the iMac's Red/Hot pink wire.  Do not cut off or damage the female pin from the iMac's LCD cable.

Another View

- On thing to consider is to put a small piece of heat shrink around around the connection to shield it and make sure it doesn't come into contact with anything


- However do not "heat" the heat shrink - leave it free floating at least for now.

Heat shrink around Connection

D) TMDS Control - Clock and Data (White and Black)

Clock and Data (White and Black) to DVI #6 and 7

- 2 wires from the iMac's Gray LCD cable should still be unhooked at this point


i) Connect "White - CLOCK" to DVI Connector Pin #6
- This is in the same Row as the Black LCD Cable's RED wires but the third pin from the end / "Analog Area"
- This pin is right behind (when facing the DVI interface) the VEDID placed in the previous step.


ii) Connect "Black - DATA" to DVI Connector Pin #7

- This is in the same Row as the Black LCD Cable's RED wires but the second pin from the end / "Analog Area"

- This pin is right behind (when facing the DVI interface) the GROUND placed in the previous step.

E) Connect DVI Cable to your DVI interface - Connect it to a source/Computer and Turn on your Power Source.

- You should see your image

V.  Problems with Sleep


- As configured the backlights will stay on during sleep as there is no signal to turn them off.

- One way to get the backlights to turn on and off with the display is to connect them to the Voltage from the Computer/DVI: The VEDID

- Note: I had expected the Purple Inverter cable to do this, but it actually didn't make a difference if this was connected or not. (May not even be necessary)

- Take the Alligator Wire that connects to the RED INVERTER WIRE.  And Unhook the other end that connects to the Red Molex 5V line.

- Take this end and clamp its teeth around the Connection between the iMac Gray Cable's Red/Hot Pink Wire and the spliced VEDID "Extra Wire".  This is the area I had recommended covering with a piece of heat shrink.  If you did this slide the heat shrink slightly out of the way and clamp your alligator wire on the pin/pins.

- Your display should now turn on and off with sleep.

Some finalization recommendations, extra pics, and of course the BLUE section for the 1/1.25Ghz pinout are coming.

In the mean time hope this guide has helped.  I've already put a lot of work into it and I hope its clear.  As always helpful comments, suggestions, and questions are appreciated and welcomed.

Good Luck!