Hacking the Apple Studio Display

I acquired a circa 2002 17" Apple Studio Display LCD in good condition from my friend and dumpster-diver-buddy Bayley Wang. The monitor is one of the top-notch 17" monitors: (Hey, it retailed for $999!) it has a superb IPS, or in-plane switching panel for unmatched color quality even by today's semi-professional standards (pros probably want 10- or 12-bit panels now). Unfortunately, this unit has an Apple Display Connector, or ADC, plug instead of the more standard DVI plug. On the flip side, the ADC is simply DVI + USB + 25V, so I could hack the monitor to use DVI! I looked on Google for previous hacks, but the only relevant documentation was a post and a PDF on the Apple discussion forums describing the ADC pinouts and their DVI equivalents. Having nothing better to do, I decided to splice a spare DVI plug onto the monitor!

Hacker food = McDonald's. Yup.

I began by cutting off the ADC plug from the single wire the came out the back of the monitor and then proceeded to strip off the rubber sheath, cut off shields, and strip the internal cables. The actual cables were 26-gauge wires -- they were very thin and looked very fragile! I used a magnifying glass to help peel off the shielding. Some of the internal wires were grouped and additionally shielded; I exposed them at a shorter length to prevent cable confusion (there were multiple cables of the same color). I repeated the process for the DVI cable: first cutting it in half, then stripping the wires, and finally stripping the wires which were enclosed in a further layer of shielding. Stripping all the cables took a good hour and a half.

The next item in our agenda was to find out which wires corresponded to which pins on the DVI wire fragment. I was not quite sure what to do initially, but a MITER gave me the following tip: Apparently the ohmmeter has the nice property of displaying some odd (i.e. zero) resistance when the positive and negative leads are connected without resistance. I tested all the pins and all the wires and constructed the following charts (note: these colors may be different for your DVI cable!):

Main correspondence table

ADC color	DVI Pin & Color (if none, function)
2x thick red	+25V
2x thick black	Gnd
very thin dark brown	C5
very thin orange	LED
light blue	7 yellow (single)
yellow	6 white (single)
green (twisted w/ white)	USB D+
white (twisted w/green)	USB D-
black (near USB Data)	USB return
light brown (t. w/ white)	24 white (white, blue)
white (t. w/ light brown)	23 blue (white, blue)
white (t. w/ orange)	2 red (red, pink)
orange (t. w/ white)	1 pink (red, pink)
pink (t. w/ white)	9 brown (yellow, brown)
white (t. w/ pink)	10 yellow (yellow, brown)
white (t. w/ black)	18 green (green, black)
black (t. w/ white)	17 black (green, black)

t. = twisted
(color1, color2) = color1 is in the same shielded group as color2

Other Pins <=> Colors on the DVI fragment

11	naked w/ yellow, brown
16	light brown (single)
14	dark brown (single)
15	black (single)
3	naked (red, pink)
22	naked (blue, white)
19	naked (green, black)

single = not in a shielded group

Male DVI-D (single link) pin numbers:

C5	8	7	6	---	---	3	2	1
	16	15	14	---	---	11	10	9
	24	23	22	---	---	19	18	17

The --- pins represent unused pins; these pins are for dual link connections only.

I was left waiting for quite a bit because I didn't know how to solder and one of the MITERs who graciously volunteered to teach me, Dane, was busy with his project. After he was done, he soldered one of the wires on the monitor end with the corresponding wire on the DVI cable fragment while I watched from the side. Then he placed a heatshrink over the freshly soldered wire and blew it with a heat gun to prevent the conjoined wire from shorting the other wires. I then sat down for what seemed to be an hour and concentrated on soldering all the pairwise wires. The end product was a great big mess; Charles Guan, the MITERS god, felt sick to his stomach just by looking at it! Everyone doubted that my hack would work, but I had a sliver of hope that my first real electronics project would succeed.

After I was finished, I showed Dane the end result. He suggested that I should solder the shields (the naked wires in the shielded groups), too. I finished soldering rather quickly, heatshrinked them, and reported back to Dane. We then connected the monitor to the lab power supply, dialed it to the Apple-specified 25V, and connected the alligator clips to the red and black wires on the monitor. Dane touched the capacitative power button, which pulsed at the touch. I connected the monitor to my laptop, went into System Preferences, and hit `Detect Displays.' The monitor then came to life in mirror mode!! My five hours of hard work paid off!

 IT WORKS!!11!!oneone!

Mess of cables

Other notes:

• USB does not work. I'll get that working this week. [EDIT] A friend suggested that the monitor might internally make the +5V required for usb, so I'll have to test it this week at MITERS since I don't have the power supply in my dorm. USB does work -- see the follow-up.
• Hot-plug display detection doesn't work. I'll get that working this week.
• I will consider making a breakout box instead of hacking the monitor cable. One of these adapters costs a whopping $99 from Apple! 
• The monitor runs fine on 24V and draws slightly more than 1A -- no need for 25V. I have already ordered a 24V 1.5A regulated power supply from ebay.

If you have questions and comments regarding this hack, feel free to leave a comment (Google account required)!

EDIT[2]: Here is a followup of the hack: http://doesntexistat.blogspot.com/2010/11/apple-display-hack-followup.html

EDIT[3]: Here it is in action: lame dual display and insanely excellent triple display