Not been on here for a little while and saw this posting.
Just thought I would mention that I did a Studio Display conversion from an ADC connection to HDMI connection a while back and for my own use I did a bit of a write up that I never quite finished…I do though still have all the pic.s, pinouts and my notes on the procedure so thought it might help for me to copy it and put it all up here.
I found that the simplest way was to take an HDMI cable, cut the end off it and then wire up all the ends of the cut off cable directly to the corresponding wires on the Studio Display so that the display now instead of having a flying ADC cable has a flying HDMI cable.
For the power supply I simply wired up a power socket jack to the case of the Studio Display and put it in place where the old USB 1.1 hub was located and used a cheap universal laptop supply that I set to 24v output.
What I didn't do, but should have done (and could not be bothered to do after I had finished the project!!) was to actually connect the USB "in" to the display to a USB cable. The reason I found I should have done that is because without it there was no way within OS X to change the brightness - so brightness is on full (which is not terrible, but not ideal). Brightness can be changed in Windows, but for OS X unless you hook that up then system preferences can not change it. So if you do a diy re-wire like me then remember that small fact.
Here are the pic.s I took while working on the job and I have attached the wiring diagrams that I found and used….
Finally, here is a copy of the write up I made, but never published!
I bought an old Apple Studio Display recently off eBay. It is one of the 15" models with the ADC cable.
I wanted to convert the display for HDMI to use, and had not seen any walkthroughs for this procedure - although there are a number of walk throughs for DVI conversion.
First thing to get is a universal AC power adapter. I got one with a voltage switch on the side for less than £10. A 60W adapter is sufficient and it must be capable of 24v output.
I also got a DC power inlet socket.
I had the luxury of a ADC equipped Cube to check the monitor forked properly before I started, so I figured it would be a good first test if I saw if the Cube could display to the screen if I disconnected the power from the ADC cable and replaced the display power with the power from my adapter. This way I would then at least know when trouble shooting later that I had a good power source - one less unknown!.
So onto striping down the display:
Here I am removing the power plug from the display, cutting the cord and re-wiring it for use with my own adapter:
Carefuly now making sure thet the 25v line from the ADC cable cannot short out inside the case I then (with power coming from my adapter now) fired up the cube and sure enough it booted through to the desktop…..
Now time to get dirty with the cable and to make the display unusable by an original cube (!).
My initial plan had been to re-use the original Apple cable and just solder on the needed wires to an HDMI plug. I bought a solderable plug off eBay and to cut a long story short…..after getting half way through the hack I decided the soldering job was too delicate for me…..so instead I took a spare HDMI cable and took that apart. However you do this though, stripping the Apple ADC connector down is useful to see the wire colors and how they are grouped and which pins they go to on the ADC connector. If like me you take the easy way out then the following strip down of the connector end is not needed. You just need the results so you can find what the cable colours and connections at the display interior mean. So I suggest you skip to the ADC wiring section to avoid boredom.
This is my strip down of the original Apple connector in the next few photos.
Note the horrible gunky stuff they put around the pins to stop you getting at them! I stripped of as much goo as I could to note down what cables went where.
Here is a pinout of the ADC connector (looking from the male end).
The signals we actually need to connect to with our HDMI connector (again cutting a long story short!) are the TDMS lines for TDMS channels 0, 1 and 2. Each of these has a positive lead, a negative lead and a shield. We also need the TDMS clock, DDC data, DDC clock and clock return
Apple seems to enjoy reversing conventions. Please note that in the apple connector all the white leads are positives, whereas in the HDMI lead I was using the whites denoted negatives. So with Apple NEVER assume that connecting like colours together will work…..
ADC CABLE ANALYSIS
The following set of leads come grouped together (for shielding):
TDMS Data 0: black(-), white(+), shield
TDMS Data 1: Pink(-), white (+), shield
TDMS Data 2: Orange(-), white(+), shield
Brown(TDMS clock -), white(TDMS clock +), shield
Other single wires we need:
Brown from C5 (DDC return), blue (DDC data line), yellow (DDC clock line) ,
The rest (that we have no interest in):
orange(LED), red (soft power),
Grouped together : green, white, black (USB data lines + - and return line)
Large leads 2 Red, 2 black. (25V and Gnd returns)
HDMI cable wiring:
I won't guess the colours in your cable but from the pins within the cable we need to be connecting up all of the following pin groups for which the descriptions match the colour coded cables listed above:
HDMI CABLE ANALYSIS
As I mentioned earlier, do not make any assumptions about the colouring of signals in the HDMI cable matching those of Apple- in my HDMI cable all the white cables in the TDMS groups were connected to negative lines, whereas in the Apple cable they were the positive lines….for that reason I am deliberately NOT telling you the colours I found in my HDMI cable and you must make a note of what you find on a pin by pin basis. it's a simple procedure, note down the colours etc. according to the HDMI pin you remove them from.
TDMS channel 0, 1, 2 [0:+ (pin 7 HDMI) shield (pin 8 HDMI) - (pin 9 HDMI); 1: + (pin 4 HDMI) shield (pin 5 HDMI) - (pin 6 HDMI); 2: + (pin 1 HDMI) shield (pin 2 HDMI) - (pin 3 HDMI)]
TDMS clock + (pin 10 HDMI), TDMS Clock -(pin 12), Shield (pin 11 HDMI)
DDC clock(pin 15 HDMI), DDC Data(pin 16 HDMI), DDC return (pin 17 HDMI)
This leaves us with:
Hot Plug Detect (Pin 19 HDMI); +5v power (pin 18 HDMI); CEC (pin 13 HDMI).
These last three I did not know what to connect to where, I discovered that CEC does not need to be connected to anything; Hot plug detect NEEDS to be pulled to a high voltage; probably the +5v pin from the cable does not need to be connected, but I connected it up to the red (soft power) lead of the display. To deal with the Hot plug detect (which when left disconnected was the one thing that seemed to be needed as the display was not seen by the PC) I actually connected it to the +5v line that is used internally within the display for powering the USB hub. I figured that as I had no use for running a USB cable to the display just to then get two USB 1 ports I could use the 5v to do my hot plug detect. I did not use a resistor here, because I guessed that the USB hub supply would be limited and that the cable would only draw a small current, some people suggest using a resistor pull up to a 5v supply but my way seems to work fine….
Hope this salvaged info from my records helps you or someone else along!!
ADC Cable Pinout.pdf 40.99KB