Saturday, November 27, 2010

The Elusive All-In-One

Let me introduce you to my new favorite form factor: The Embedded Compact or ECX.  When I took this out of its box, even though I knew its dimensions, I was shocked at how small it was.  I do want to caution that everything with these boards is proprietary including its cables and proprietary = expensive.  So know what your getting yourself into.  I've seen these available in either Atom or most excitingly Mobile Core 2 Duo configurations as this one is.
For perspective I have included a picture with a metro card (credit card sized).  To demonstrate how small these boards are.  The have the same dimensions as a 3.5" drive, but they are also quite thin as the mobile processor fans are small and the ram inserts horizontally on the underside of the board.

In terms of features you can see the PCIe x 4 slot, a DVI/VGA/HDMI out.  However, there is actually an LVDS out as well inverter pins (yes the entire LCD conroller is embedded in this tiny motherboard).  So you could connect the LVDS cable and inverter directly to this motherboard without any additional hardware.  Now the question is can the native LVDS resolution drive the iMac's 20" screen? And does this solve the problem with the inverter for the 20" iMac - maybe?

The underside shows the RAM (4GB) in place (purchased separately) as well as a slot for a Compact Flash Card.  This I also find to be a fantastic addition.  I need all the space I can get and although I am not sure, I would be surprised is an embedded board was unable to boot from the compact flash memory. This could mean with a 64+gb card no need for a hard drive, no extra heat or power, and a much faster system.

Here is the 2.53 Ghz Core 2 Duo Mobile (Socket P Penryn Processor) and its very reasonably sized heat sink/fan.

This is the first board that I have felt makes an all-in-one doable.  I have never liked the idea of shoehorning a mini itx or mac mini into the base at an angle.  Plus I had extreme concerns about airflow.  I imagine this sitting above the dvd drive with the cpu fan around the same place as the iMacs original fan.  This board also allows incorporation of a dvd drive.  Although not necessary anymore, I always felt it was part of the iMac's charm.  In addition, if no other hardware is required that would leave the bottom for placement of a powerwave adapter (to use the original speakers) as well as extenders/ports to make the rear I/O look as original/professional as possible.  It does use a power brick, but I am certainly ok with that as no internal powersource = less heat.
Now I could find this board impossible to work with, it may not fit at the top of the base, it may require a hard drive.  I don't know, but keep this in mind the original iMac was an embedded compact motherboard, it only makes sense to use something along those lines.

I already know I can thread LVDS cables down the neck into the base with a replacement 20" LCD.  However, I could also try to splice the existing panel to DVI.  I'm not sure which way I'm going to go - but I am leaning towards LVDS (if the native resolution is compatible) as it is embedded onto the motherboard, thus will turn on/off with the motherboard etc.  For people interested in doing this, you will need extra LVDS cable.  The best place to get it is ebay.  I find cables used in flat screen tvs are usually longer and of more use.  Examples of LVDS cables from tvs are shown in the pic on the right.

The biggest problem I'm going to have is with that damn 20" inverter (I am not running high voltage cables through the neck again - too unsafe).  Unlike the 15 and 17" I have not been able to get it to work independently.  Although there are pins for the inverter on the motherboard, it is one short.  I believe there is some voltage difference involving orange and yellow that turns the inverter on.  I am hopeful that maybe by having an active dimmer hooked up that this may solve the problem.  Obviously using the native inverter with the motherboard would be option number 1.

Option 2 would be to locate some other aftermarket inverter that will work.  I have yet to find one that is "flat" enough to fit in the monitor casing, but I haven't looked for sometime.

Option 3 is something I have recently begun to play around with and that is led lighting.  I could try edge lighting the lcd glass, replacing the CCFLs with these superbright leds from environmental lights.  These work on a 12v dc line which can be supplied directly from the motherboard without need for an inverter.  This is a 6 foot roll.  They do come brighter however, this requires a 24v dc line.  If this is not bright enough, I may try led back lighting instead of edge lighting.

Option 4 is using the 17".  Although I'd prefer the 20", if getting the backlights to work on the 20" proves too difficult, I already know how to do so with the 17".  And would be quite happy with a fully all-in-one modernized 17" iMac G4.

I'd love to hear advice from people who have some know how with led backlights etc.  And as always I'd be happy to answer any questions.

17" Inverter Pinout/Instructions

To test pinouts I would recommend getting either a molex or sata to ac adapter such as this one:
By sacrificing an inexpensive molex splitter you get 2 12V, 2 5V, and 2 Grounds without having to deal with the hassle of an atx power supply.  It also comes with a handy on/off switch.  These are available from newegg for pretty cheap.  I would recommend getting an sata one if possible however, as that will give you a 3.3V line as well.

To get the 17" inverter to work you will need a source of power, the screen and inverter, as well as a couple 1Kohm resistors (mine were rated 1/2 watt).  Here is the pinout and connections on the right.

Interestingly I was unable to get the inverter to light without a resistor between the green and the 5V line.  I expected this with the purple, but not the green.  Also note that I am pretty certain the native power supply to the purple is actually 3.3V.  As it is simply an on/off I doubt the extra voltage will matter, but long term I can not say for sure.  If you have an sata power source you should try to use the 3.3V line and if it works I'd probably lean towards using the correct voltage.

As you can see I left the dimmer floating, there are various ways of making a dimmer, but it is not necessary as the backlights appear plenty bright by using this method.  Just as a reminder for those of you hooking up to a molex/sata power supply.  YELLOW = 12V, RED = 5V, BLACK = GROUND, GREY = 3.3V (only on sata).  There is also nothing wrong with using an atx power supply and its various voltages, I simply found this easier.

*NOTE: After hearing from a reader that the screen flickered with the Red line connected to 12V and stabilized when connected to 5V (and then confirmed by another reader) I decided to recheck it myself.  And 5V is indeed the correct voltage.  I then went and looked at my old notes which showed "Red - 5V".  I made an error when originally making this chart.  I apologize for any inconvenience and have updated the above chart.

Saturday, November 13, 2010

Revisiting the G4

Part I:

So much for changing gears. I have taken a long break from the iMac G4 mods but recent developments have gotten me excited to revisit the designs. First, the excellent work done by the folks over at macrumors especially pgee70 who has solved several of the problems caused by splicing dvi directly to the 15" monitors tmds cable.  As well the original japanese modder who performed the first successful splice.  I encourage anyone interested in this mod to check out their work.  One of the most annoying components of this mod is opening the neck and the ability to avoid doing so would be a gigantic step forward.

Secondly - cheaper and lighter touchscreens.  Although most do not seem to share my enthusiasm for the iMac G4 as a touchscreen computer, I can say firmly that it is far and away the best design for a touchscreen computer I have come across so far.  I know companies patent everything all the time but here is apple's patent filing for a touchscreen imac courtesy of engadget.  Look Familiar? My touch screen 17" mod makes a fantastic kitchen / family room computer.  It functions as a small internet TV, video jukebox, and web browser.  Now we are seeing capacitive screens available at a reasonable cost.  However, the iMac does have a fatal flaw with touchscreens - they MUST be light.  Because all the weight is placed at the front of the iMac this often causes problems with "arm drift".  Especially with the weight sensitive 15".  However, new film-to film touch screens eliminate this problem as they are essentially weightless.  So, I will try the15" DVI splice mod, but I will also incorporate a film-to-film touchscreen.  My goal will be to not open the neck if possible and use only the extra wires (microphone/LED/dimmer) to connect the resistive screen to the base.  Although I have read that people have done the same with the 17" there is no pinout or instructions available online.  I know many people are interested in converting their 17" using this splice technique and I have plenty of extra arms and iMac components to compare and experiment with - so coming up and verifying a pinout of the 17' should be possible.

I will be posting a parts list for the 15" mod shortly, and will post updates as I move along.  I will try to work on the 17" pinout and guide as well, though will unlikely take this to a completed mod.

ADDENDUM: As you can see from my recent posts I have decided to bypass the 15" and focus on the 17 and 20" iMacs.  The 15" mod has been done several times and I believe replicating it won't really add much to the community.  Still, if you are doing this mod and need any help beyond what is available from macrumors and other sites listed, I'd be happy to answer any questions.

Part II:

Other newer developments include smaller form factors.  I have yet to complete an all-in-one - my 17" hides behind it a computer.  It is possible to shoehorn a mini itx board at the right angle into the base or a caseless last generation mac mini.  Despite this - I would be very hesitant to put anything hotter than an atom-ion combo in the base.  The G4 was designed as a convection cooled computer.  The airholes are located next to the exhaust fan and the mobo is otherwise surrounded by a heavy metallic faraday cage.  So there is NO air movement at the bottom of the dome.  However, some decent smaller form factor boards specifically the embedded compact have just come on the market.  Although they use mobile processors - a core 2 duo is would still make for solid computer.  Also, using the splice technique no monitor components will waste precious space in the dome.
The 20" still remains the toughest challenge.  While it takes only a power source and a few resistors to turn on the backlights to the 15" and 17" mods - I have never been able to get the inverter to work unless connected to the original iMac.  Because no aftermarket inverter is thin enough to fit inside the monitor casing - it has to go in the dome.  As a result, there are 6 high voltage wires that need to traverse a moving metallic neck.  It was because of this that I disassembled my original 20" mod.  I did not believe I had adequate shielding on the wires.  However, I have recently come up with a possible solution that I will be investigating in the next few weeks.  Thanks for following along and as always feel free to ask any questions.

Sunday, April 11, 2010

17" iMac G4 LVDS Conversion - Video

Video of 17" iMac Mod

Here is a video of the mod in action.  I have connected it to a small mini itx computer running Windows 7.  As I said before, I do plan on getting a mac mini for this mod eventually.  I wanted to get a general sense with how the leopard user interface would work with a touchscreen, so I skinned the computer to look like leopard (using Rocketdock and Apple Icons).  The user interface works great.  Having the dock makes selecting programs easy.  With this networked computer I am only a few touches away from my entire home movie, picture, and music collection.  In addition, using Webtaps for firefox allows me to rapidly select videos from internet sites such as hulu.

To complete the look I am using the iMac G4's original keyboard (I like using the wired keyboard because I plan on concealing the actual computer, this gives me two easily accessible USB ports).  I have also added the magic mouse and the USB griffin powerwave adapter which allows me to use the iMac's original Orb speakers.

I hope that this blog has and will help with similar projects.  For myself, I have decided to next work on an ATOM/ION G4 Cube mod.  Similar mods to this have been done, but I think having a slot loading bluray home theater pc (capable of HD output) in the shape of an apple cube would look great in the family room.  Also, I hope to get back to a multitouch table that I had been doing some work on.  So one mod done and on to the next......

Friday, April 2, 2010

17" iMac G4 LVDS Conversion - Completed

UPDATE (11/4/11): Although not quite as worrisome as the 20" TMDS to LVDS conversion, I still recommend against using this method as high voltage inverter to CCFL wires go through the metal neck.  Please see my summary of mods or my 17" Step by Step Guide for an easier, more stable, cheaper, and safer way of doing this.

Original Post:
I actually get to write this post from my completed mod!!!! (Well from my laptop cloned to my monitor, but close enough).  I think it came out great.  The image is clear and bright.  The touch screen adds some weight, but there is no significant "monitor drift".  It took a while to get the touch screen working and calibrated, but it works fantastically.  In most situations I think touch screens on desktops make little sense, but for the G4, the ability to grab the screen move it towards you and  tilt it up makes it extremely fun and useful.  It's not multitouch, but that's OK.

This is the end of a really fun experience.  I think this is the perfect compromise between my two other mac mods and I do have to say that I actually think I prefer the proportions of the 17" vs. the 20".  For anyone debating - after doing both - I would strongly recommend the 17" over the 20".  The components are MUCH cheaper for the 17".  Also, 6 backlights in the 20" leaves a lot of voltage to travel through the neck.  The 17" allowed me to add much more shielding to the cables and made the mod significantly more stable and I still had enough room for a touchscreen.

I'll add a video in the near future to demonstrate the touch screen functionality and the mod in general.  When I became interested in doing this - I was shocked by how many others had similar ideas and I hope that this blog has helped and inspired others that are attempting to do a similar thing.  It is very doable and there is nothing that you can buy in a store that comes close to a one of a kind device that you build yourself.  That reminds me I'd like to thank fellow iMac G4 moders Blugray and MacOdyssey whose blogs and posts inspired me and without whom I never would have been able to finish (or even start) this project.

I have to admit though its a little weird to see Windows on the iMac G4.  I may have to get a mac mini for this computer, I'll just have to hide it under the desk .... ;) As always, I'm happy to answer any questions.  Good Luck!!

Saturday, March 13, 2010

17" iMac G4 LVDS Conversion Process

Again, this is no longer the preferred method, the TMDS to DVI is better in every way.  To keep my blog better organized, I have combined several posts into this one post detailing this conversion.

I. Parts List
This is a list of parts that I will be using to construct an iMac G4 17" Touch Screen which will be used as an external touch screen monitor for a separate computer.  I am waiting on delivery of the monitor.

1)Broken iMac G4 shell.  (includes monitor back and front bezel, 17' iMac Neck, superdrive cage, base with faraday cage.)

2)Monitor - HANNS G HB171DBB (This is the model with DVI, its 16:10, uses an LVDS wire and not a ribbon cable)

3)17" 16:10 4-wire resistive touch screen.  Purchased from easyworldwidetrading (Hong Kong based company) on ebay

4)Wires: A)For LVDS cable -  shielded cables from the neck of a 15" iMac neck and 17" iMac Neck.  Depending on how many wires the LVDS cable on the Hanns G has.  The TMDS in the iMac cable uses paired wires with a third ground that wraps around the pair (Most LVDS cables have paired wires with a few ground wires mixed in and then 3 12V cables).  I would prefer not to use the ground wires for signaling.  The 17" TMDS cable in the neck has paired wires (which are >30 gauge) and are very difficult to work with in the black cable and larger wires (28 - 30) gauge in the grey cable.  The 15" neck cable has 28 - 30 gauge wires (about 20 including grounds and 15 excluding grounds).  I will likely then use both the grey cable from the 17" and the only cable from the 15" (remove the black cable).  I am interested in using the existing cables because they were designed to withstand the stress of movement in the neck.  If I do have problems with this I may purchase additional long LVDS cables or use 30 gauge Kynar wire.  I know this is confusing but I will include details and pictures of this when I start this mod.
             B)For 4-Wire Touch Screen - shielded controller to inverter cable from the existing 17" imac neck (this has 6 wires, I will be using 4 of them).  This is really nothing more than usb wires and they appear to be about 24 - 26 gauge.  If there is a problem with these I will use cat5 wire, but again I am trying to use as much well protected native iMac G4 wires as possible to increase the longevity of this mod.
             C)For Inverter to Backlight Cable Extensions - High voltage pink and white 15" inverter extensions x 4.  I have six of these but if you place them right 4 should be OK.  The extensions I'm using I bought on ebay (they were from HP Omnibook laptops).  They worked well with the 6 backlights on the 20" monitor.  Because the 17" only has 2 backlights (one pink and one white wire per backlight) and it takes about 26" to make it from the corner of the monitor to the middle of the base, 4 of these would be sufficient.
              D) Extenders - 6" VGA extender, 6" DVI extender, 6" three prong AC power extender, USB extender.  These are just short male to female cables that will allow me to have ports at the back of the base to attach cables to and not just random cables coming out the base.  This is actually very important.  If the cables get pulled from the outside you do not want them to pull at and damage the lcd controller and power source inside. 
              E) Buttons/Keypad - I am hoping that the keypad on the Hanns G is small enough to place on the back of the base.  If it isn't I may need to solder new buttons - but we'll see.

5)Something for IN the base - For my 20" I used a bluray drive hooked up to a computer by SATA to USB converter.  Bluray on a 17" monitor seems somewhat pointless (not that 20" is so much better).  I could do a standard DVD drive, Airport Base Station (thanks Roger), Large external hard drive? I know the ultimate goal would be a small itx computer or mac mini.  Unfortunately, I'm worried about heat issues with most mini-itx mobos.  Remember the base is not empty, it has the lcd controller, power source/inverter, and lots of extender wires which all take up significant space.  As far as the mac mini is concerned, it would likely have to be removed from its case.  Because the mac mini is so small, I'd hate to damage it for this mod when it could be easily hidden or displayed outside the base.  Plus, putting any computer in the base will eventually make it obsolete and require upgrading.  I have room for something the size of a 5.25" drive, if anyone has any ideas please let me know.

6) Griffin PowerWave Amp - For using the Apple ProSpeakers

7) Tools -
                 Torx set for taking apart the iMac
                 Soldering Iron and solder
                 Helping Hands (alligator clip soldering assistant)
                 Shrink Wrap (Highly recommend over electrical tape - these are tiny wires and if the tape comes off and two wires touch, at best you will loose signal, at worst you could fry your LCD screen)
                 Heat Gun (for shrink wrap)
                 Hot Glue Gun, Modeling Clay, or Silicon Gel to secure the extenders to the base

This list may change as the mod proceeds.  I will give specifics and images as I use materials.  But, if you have any questions just comment below and I'll do my best to answer.

II. Monitor 

The Hanns G Monitor arrived today and from external inspection, it appeared as advertised.  The keypad is reasonably sized and there is a DVI connection.  But, what is most important is what is inside.

First unscrew and remove the stand.  Then, using a flat head screwdriver pry the front bezel from the bottom.

With the back of the monitor exposed you can cut the aluminum tape with an X-acto knife.

Remove the inverter cables from the inverter using a needle nose pliers.  Of note, there are two inverter cables with both a high voltage (pink) and low voltage (white) line.  The inverter cable connects to the inverter via a 3 pin connector. (Only 2 pins are used and the center channel is empty).  Because my inverter extensions use a 2 pin connector I am likely going to have to change this cable to a 2 pin connector and re-use the three pin connector to connect to the board at the far end. 

We can now get a good look at the LVDS connector.  We can clearly see 16 wires arranged into pairs.  8 total pairs (Black/White. Brown/White, Red/White, Orange/White, Yellow/White, Green/White, Blue/White, Purple/White).  These paired wires use LVDS (small differences in voltage between the pairs) to transmit the image.

I have identified the 3 ground wires by white arrows.  These are the independent red, orange, green wires.

The three remaining wires at the lower portion of the picture designated by the black circle are the 12V wires.  These wires are black, brown, and yellow.

This makes for a total of 22 wires, significantly less than the 27 wires of the 20" mod.  Knowing  which wire carries what signal is important as we decide what wire we will use to extend this cable.

III. Cables
Options I am considering include the original iMac cables.  Shown here is the cable for the 15" iMac.  This cable includes 14 wires and 3 grounds of a slightly smaller gauge than the existing LVDS cables.  The 17 and 20" use a grey cable with 9 wires and a black cable with 4 wires which split into triplets (pairs + a ground).  The black cables wires are way to small and impossible to manipulate.  The grey cable appears to have wires of similar gauge to the 15" iMac.  The advantage to using existing iMac cables is that they come shielded and are already the proper length.  However, they are designed to carry a TMDS signal.  On inspection not all the wires are the same, some are smaller in gauge.  Because LVDS involves very small voltage differences between two pairs, I am concerned about the effect of using wires which may vary slightly in gauge and thus resistance.  Although I'm sure I could produce an image, if I choose poorly, it may be distorted.

After considering this, I am leaning towards using LVDS cables.  These can be purchased online.  I do not have cables long enough, but because I intend to splice them to the existing LCD connectors at both ends anyway, I am not concerned about lengthening them.  Using this method will leave me with unshielded cable, so I will have to use magnetic tape and heat shrink to shield the cable.  Because of the significantly fewer cables in the 17 vs 20" mods, I am not worried about the fit in the neck.  Right now, I feel as though I'd rather be confident in my connection, using LVDS cable to connect an LVDS signal and add my own shielding rather than using shielded TMDS cables which may have subtle differences between individual wires.  I may however reconsider this.

IV. LCD Controller

To completely free the LCD controller and inverter/power source, you need to unscrew the AC plug with a phillips head screw driver and use needle nose pliers to unscrew the bolts surrounding the VGA and DVI inputs

One of the "quirkier" aspects of this board is the fact that the controller and power source plug directly into each other via an 8 pin connector.  This can be seen in the center of the image.  To extend this I am going to use 2 4-pin USB extenders that end with 4 male pins.  These cables can be purchased at specialized computer stores such as frozencpu.  However, before I go any further and assume this will work, it should be tested.

Thats all for now.  The to do list includes:
       Test extended LCD controller/Inverter
       Determine LVDS vs. existing iMac TMDS cable
       Determine which cable will be used to extend touch screen
       If using LVDS, which shielding should be used
       Change inverter connectors (Change pins vs. cut and solder)

Once these issues are ironed out wiring through the neck can be done.
One of the unusual features of this board as I've mentioned is how the controller plugs directly into the power source/inverter.  Before we go any further its important to make sure that it is possible to extend this.  Using wire extenders (I have a 4 pin and a 5pin) there are 8 pins to extend.  So 1 wire is essentially unused.  Using these extenders, a clear image was produced.  So, one problem solved.

The second issue is the 3 pin cables that connect the backlights to the inverter.  Using a safety pin to release the pins, I attempted to switch the connectors from 3 pin to 2 pin.  Unfortunately, the pins on the monitor are too large to fit in the 2 pin connector.  There are two possible solutions, for one I could switch the LCD glass onto the backlights for the native iMac lcd.  The only concern I have with this id that I am not sure the backlights on my monitor work (I have a broken iMac G4 that has never turned on).  Before I can consider this, I'd have to test the backlights.
        Alternatively, I can simply cut and solder the backlight wires onto the proper connector.  Although this would be a permanent change, it should work just fine.

So, I've decided to use LVDS cables and add my own shielding.  As you can see there are more wires on my LVDS cable (right) than on the LVDS for the Hanns G Monitor (left).  That is fine as the extra wires are easily removed.  In this case I need 22 wires.  Although there are more cables, the basic layout of LVDS is the same.  You can see several paired wires and 3 wires on the left of the connectors that carry the 12V charge.  When buying LVDS cable online do not worry if there are more than 22 wires.  It does help to have an extra 30pin connector, but even if it is different, you can always use the connector that came with your monitor by either gently removing the pins and replacing them with the pins from longer lvds cables, or cutting and soldering the wires.  You need about 120mm of lvds cable to make it from the back of the monitor through the neck and into the base.  I personally do not have LVDS cables that long.  As a result ill be splicing 2 lvds cables (50+70mm) together.

LVDS cables are easy to extend if you take care to not cut the pins.  By placing the male and female pins together and adding a small amount of solder you'll have a solid connection.  I also highly recommend heat shrink (with a heat gun).  I find that electrical tape can easily fall off these small wires (especially with these wires that will be moving with the neck).  You do not want the exposed solder joints to touch (This could damage your LCD if the wrong wires touch).  Also, using a multimeter with a continuity mode can help verify your connection.

Now that I have my lengthened LVDS cable, the next step is to shield it and put it through the neck with the inverter extensions.  I will also have to decide how I want to lengthen the touch screen wires.  There will be a lot to do this week.

Taking a closer look at the LCD controller.  The Blue circle connects to the keypad.  The Green circle is the LVDS cable.  The black box on the lower right of the board is where the controller connects directly to the power source / inverter.  The board is 6mm x 9mm.  Note that this does not include connecting a DVI or VGA cable.

This is the power source /inverter.  These boards will be larger in AC powered monitors.  DC boards may have the power go directly to the LCD controller and have an external power brick.  This board has AC in at the green circle.  This gets converted to DC and outputs to the lcd controller at the blue circle. (You can see my extensions hooked up) The AC power also gets routed to the bottom of the image which are the inverter outputs.  These (red circles) are where the cables that connect to the backlights are placed.  These are 3 pin female connectors (although only 2 pins - 1 high voltage, 1 low voltage are used).  This board is 18mm x 12mm.  This board will fit into the iMac base without difficulty.
V. The Neck
This is the "new LVDS cable".  To make it easier to fit through the neck and the back of the iMac.  I divided it into 2 parts (similar to the silver and black cables in the native LVDS wire).  I added shielding with aluminum tape followed by heat shrink.  I did this both to protect the wire and also to prevent interference from the neighboring high voltage inverter cable that will be running through the neck alongside it.  Unfortunately, completely not following my own recommendations, I started adding shielding before remembering to label my wires.  So, I'll have to spend some time with the multimeter to verify my wires.
This 4 pin extension cable (the same exact cable I'm using to extend the LCD controller to power source connections).worked successfully with the touch screen and is long enough to go through the neck without any further extension.

I simply had to gently remove the bottom pins to allow for passage through the neck, then put the connector back once the pins are through.

I have previously detailed how to open the neck on this blog, so if you need help with that just scroll back several pages. I wired the inverter extensions in first (It takes 2 to make it through the neck, so I connected them in the center).  These are the pink and white wires.  I am not going to lie, it can be tough to get the wires through and if you knock the spring off its mount, it can be difficult to get the spring back on.  But, it can be done.  Finally I wired the touch screen cable through.  Unfortunately these small, thin wires barely fit as is.  I was unable to add shielding to this cable as I had hoped, with the other cables shielded I don't expect this to be a problem, but we'll see.


Above is the top of the neck.  You can see 2 inverter extensions with red arrows, 2 LVDS extension cables labeled with green arrows ,and 1 touch screen extension cable shown with a blue arrow.  The 2 LVDS cables join to one 30 pin connector that will plug into the monitor.  You will notice two "bulges" in these connections.  This is where I extended the cable, because the inverter cables will be away from the cable at this point I'm not worried about interference.  Also, because the wire is thicker here, I wanted to be able to flatten these wires out as it is a very tight fit in the monitor casing.

Below is the bottom of the Neck, you again see the cables labeled in the same manner.  The bottom cables will need to be soldered to the Hanns G monitors lvds cable and then the extension will be complete.  As I commented before, I will need to use a continuity test to determine which wire is which (Always label your wires).  

To Do List for this week:
- Continuity test / Wire Labeling
- Solder final part of LVDS cable
- Decide on which method to use to connect 3 pin inverter connector to 2 pin extender
- Test the Neck Wires

If the test is successful, I intend to begin assembling the mods base/monitor by next week.
As I had previously mentioned, I had forgot to label the wires, so I had to spend some time with a multimeter to figure out which wire is which.  The system I use is letters as you can see here.  However, by forgetting to label the wires and having to use a continuity test I located a small problem and was able to repair it.

I was actually short 3 70cm cables so for 3 cables I spliced two shorter cables together.  It appears when I was pulling the wires through I snapped the pin off one of these splices.  Although it was a pain to reopen the neck and fix the broken connection, I had known where the splice was, cut through a small section of shielding, stripped and soldered the wires back together.  Yes, I would have located the problem eventually anyway.  But, plugging it in and not have it working - would have been a great disappointment.  So new advice, label your wires, but no matter how good you think your soldering skills are - get a multimeter and do a continuity test.

So with the wires labeled, its time to splice them to the Hanns G monitor's short LVDS cable.  Just to be safe I only remove the wires from the connector as I solder, so there is no confusion as to which wire goes where.  To remove the pins, use a safety pin to lift up the small tabs.  If you're gentle, you can actually save the connector for use on another project.

So 22 more connections soldered and heat shrinked and we should now have a fully lengthened LVDS cable that is compatible with this monitor.

The next problem is the 3 pin inverter cables, while my extensions are 2 pins.  I hate permanently damaging things, that's why I like to use connectors when possible.  My options are changing the LCD glass onto different backlights (such as the native iMac G4's) or cutting and soldering (the pins are different and can't be swapped).  Because changing the glass can result in damaging the LCD and I feel as though I'm already "in too deep" to worry about salvaging this LCD for another purpose I am going to cut the inverter wires from the back of the monitor and replace them with wires that have a 2 pin connector.  Plus, I don't even know if the backlights on the iMac G4 LCD that I have work as the machine was purchased broken.

So, I am leading towards cutting and soldering.  But, before I cut the inverter cables it appears it is time to test the LVDS cable.  This is the part I'm most worried about because I feel I have already demonstrated that the inverter extensions work in the 20" mod.  So next the big test.....
I have never been so happy to see the target website.  As you can see in the picture, I am testing only the LVDS cable. The controller and power source/inverter are now plugged into each other, seen at the green circle.  Although I have previously demonstrated that they can be extended, I wanted as few variables as possible.  This does not test the inverter extension (or any interference these cables may produce).  Because the 17" has only two backlights compared to the 6 on the 20", I am very confident that they will work.  So, the native inverter cables are hooked into the inverter as seen in the blue circles.  The monitor is hooked up to AC power and a laptop via VGA denoted by the yellow circles.  The LVDS signaling runs through the neck (red circle).

Please let me give one word of caution - although it may seem obvious.  The reason I altered my 20" iMac mod with the touch screen and shelf on back was that I burnt out the power source.  I was creating a more permanent shelf and simplifying the wiring.  I was tired and being careless.  Before I was about to reattach the components to the back of the monitor, I wanted to test them to make sure everything still worked.  I placed the components on my table and hooked them up.  I didn't even realize that the edge of the power source was sitting on top of a sheet of metal.  One loud pop later I had ruined my mod.  So just remember to make sure you test on top of a non-conductive surface and that all conductive surfaces are clear.

So lets cut and solder those backlights, then its on to screen test #2.  After that I'll add the power source/inverter to lcd controller extenders back and then test the touch screen.  But all in all, I couldn't be happier so far.

VI. Inverter

To lengthen the inverter, I've chosen to cut and solder.  I have these short inverter cables (I bought them on ebay for about $3).  They are replacements for a macbook pro.  I will use these along with the cables that come off the monitor and connect to the 3 pin inverter connector to create adapters.  The reason I am doing this instead of cutting the wires I have going through the neck is because I want to preserve the neck as is.  I still have the option of changing the lcd glass to a different backlight and I have no interest in reopening up the neck if I screw things up.

I simply cut this cable in half and soldered it onto the existing backlight cable on the back of the monitor.  I used shrink wrap, but I will also reinforce this with electrical tape.

I then soldered the 3 pin connector wire from the Hanns G monitor to the remaining female half of my "macbook inverter cable" to create a 2 pin to 3 pin adapter cable.  Now let's test it.

Test #2 looks great!!!

You can see now that the inverter cables (red circles) go through the neck with the LVDS cable (green circle).  I still have to test this with the Inverter/power source to lcd controller extension.

 So here is the full test:

I placed the notebook there to simply hold down the extension wires that were getting in the way.  The extensions are connected (purple circles).  All wires remain going through the neck (inverter - red circles and LVDS - green circle).  I know the picture isn't great, but the image is perfect.  There is no distortion and the backlights appear to be nice and bright despite the additional length.

The only thing I do have to test is the touch screen extension, this I will do separately.  Other than that I am extremely happy with how everything is going and can fully endorse purchasing this monitor for the purposes of this mod.  It remains possible that I will still have to switch the LCD glass if there is a problem with either weight or fit.

The next step is to assemble the base.  I am actually leaning towards either an optical drive or nothing except for the monitor components in the base for now.  I want to be careful about putting too much in the base.  I am confident that I can fit the monitor components and keep them well protected and cool as long as I don't get overzealous.  I have purchased all my extenders and am going to try to make this mod look as professional as possible.

VII. Base
So after a long time taking things apart, its finally time to put something back together.  By dividing the LVDS cable in to two parts, it easily fit into the grooves on the base's attachment.

I stripped the base entirely to maximize the room available for the monitor components.

Because it is the shortest cable, the first component to be installed is the touch screen controller.

I secured all the connections with electrical tape.  Because the controller is so small and light, one screw is all you need.

The next component is the lcd controller.  Before I installed it, I secured it to my VGA and DVI extender.  These are simply male to female connectors that will allow me to make "ports" on the back.  Securing these to the back will also ensure that there is no accidental pulling of the internal components if one of the external wires gets caught on something.  This will also improve the aesthetic look of the monitor

Secure this in the base with a couple screws and its on to the inverter/power source.  After lots of contemplation I decided against putting anything additional in the base for now.  An optical drive will fit by placing the power source/inverter above it, but similar to my 20" mod, it will make things VERY tight.  The other thing to note is that this particular power source has somewhat of a funny shape to it as a result of the direct connection it has to the lcd controller.  It is actually longer than the power source for the 20" monitor.  The other factor is that I am not making this an all-in-one, so it will be connected to an external computer.  Both a mac mini and most laptops have optical drives, so this one would really be superfluous.  On the 20" I thought blu-ray was a worthwhile add on, but its hard to justify on a 17" screen.  So, I may add one later, but for now, I am not going to add any additional components.

So the power source.   To make sure there is no aberrant conduction, I dremeled a quick acrylic housing (seen in yellow).  Screwed on the power source and then mounted them both int the base, leaving room for the wires comping from above (the touch controller and DVI/VGA extenders).  I also connected the two 4-pin extenders to lengthen the connection between the controller and power source/inverter.

VIII. LCD Housing

Putting together the monitor is fairly straight forward.  It is important to secure the cables to the back of the monitor and make them as "flat" as possible.  It is a very tight fit.

While the monitor itself is about the same size and weight as the native iMac G4's monitor, there are some differences.  The LVDS cable is in a slightly different location and there are no grooves for 4 plastic pieces that are on the front bezel's grey border.  You can either switch the entire LCD glass to the native iMac's backlights or you can simply dremel these 4 pieces off, I chose the latter.  Although these screw into the monitor and ensure a snug fit, as I am adding the touch screen in front of the monitor, I did not want a very tight fit.

I added some clear mounting tape to secure the touch screen to the front of the monitor and placed it into the front bezel and monitor casing.  I then closed it up.

I added a short 3 flat pronged power cord extender, attached the keypad to the back panel so I could access the buttons.  Eventually I will alter the iMac and secure these to make easy to connect to ports on the back of the iMac.  However, for now I just ran them out the holes in the back because its time to finally see if this mod works.

See The iMac G4 17" TMDS to LVDS Conversion - Completed for Fully Assembled and Working Pics