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#13661 - 01/10/11 11:17 AM looking for pinout for apple cinema display
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
I have here an apple 30" cinema display and power brick, where the connector between the brick and the display cabling is badly damaged on both sides by arcing.

I'd like to take the pack apart and hard-wire it to the display. (or depending on the number of contacts needed, I may use a 4 pin molex like what's used on 3.5" IDE HDDs)

I'm having problems finding a pinout for the connector. There are several things that use that same shape connector, including all the cinema displays and mac minis. The connector is not keyed and can be plugged in 180deg and work the same. From what little I've been able to find on it, the display's white LED should flash a warning if the wrong pack is attached, leading me to believe it has a method similar to the magsafe for standard communications and negotiates between the brick and the display before sending power.

The only other way to fix it is to find a new brick and a display I can salvage the cable from, and figure out how to take it apart. Costly and a lot of work compared to my plan. Probably involves finding someone with one with a busted LCD panel on ebay that can provide the entire display with cable and brick. I'd much rather just fix this one, I don't care about cosmetic condition when I'm done so long as it works.

I haven't gotten the pack cracked open yet, it's a bit of a chestnut if you know what I mean. It may not be too difficult to figure out the wire mapping, I'm just posting this request now in advance in case I need the information.

--

having cracked the nut open, it's merely two power wired (+24.5v DC) plus a drop resistor for one of the pins (60kOhm) probably to identify the pack to the display. It appears to be a top and bottom row of 5 pins each, speculating the top and bottom of each row are common, plus the leftmost and rightmost common and the next left and next right also common. (drop resistor may bridge the upper and lower center) they're really charred up.
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#19268 - 11/18/11 05:49 PM Re: looking for pinout for apple cinema display [Re: Virtual1]
hexdiy Offline


Registered: 11/18/11
Well Virtual1,
having recently acquired a possibly broken ACD 20"without a power brick, I have been desperately trying to find the power connector pinout. Nearly nothing to be found, actually. Your post here, however, has been of great help.
Extensive reading combined with my own measurements, and guided by your above post, show the following:
(let me try to visualise the prolongued o-shaped connector by text only)
1 2 3 4 5

6 7 8 9 10
(Note:Since the connector is reversible/flippable as with the magsafe connectors, upper and lower rows are interchangeable as you have stated already. So indeed note that upper 1 is linked to lower 6, upper 2 to lower 7, upper 4 to lower 9, upper 5 to lower 10, as you have stated already.)
Pinout:
1+6+5+10: +24.5V DC CONFIRM POSITIVE
2+7+4+9: -24.5V DC CONFIRM NEGATIVE/COMMON; ALSO CONNECTED TO PSU/FIREWIRE/USB CABLE SHIELD/SLEEVE, THOUGH NOT TO THE BIG DVI CONNECTOR COMMON CONTACT.
3+8 : SENSE LINES, none of them connected to common ground unlike faulty statements on other forums like the Apple Support Discussions (https://discussions.apple.com/thread/2086442?start=180&tstart=0)!
BEWARE: THIS IS THE OPPOSITE FROM WHAT YOU WOULD EXPECT IF YOU KNOW YOUR MAGSAFE PINOUT (http://pinouts.ru/Power/magsafe_power_pinout.shtml)
NOTES:
- Though I am not 100% sure that the nr. 2+7+4+9 pins carry common/negative, I'm absolutely backed up in this because they are all connected to PSU/FIREWIRE/USB CABLE SHIELD/SLEEVE. It simply does not make sense to attach a POSITIVE voltage to those (except in vintage Swiss Nagra tape recorders or vintage UK cars, both the Swiss and the Brits always have been a bit awkward, haven't they :-))
- You can forget about the nr. 3+8 middle contacts, I suppose. Seeing that the so called 'Jacobean Fix' for malfunctioning 20"and 23" ACDs is to isolate these pins, and another to just use a 30" 150W power brick instead. Which in turn leads me to believe the latter have no pulldown resistor at all. Source: once again the above giant https://discussions.apple.com/thread/2086442?start=180&tstart=0 link
- Seeing I have no power brick, but also knowing the old Powerbook 24.5V 65W PSUs have just sufficient specs to power the 20", I am going to make a connector matching the proprietary Apple connector on the ACD screen breakout from a carefully dimensioned 8.5mm wide piece of blank copper double sided component board, IF NEED BE WITH A LITTLE SOLDER THICKENING. The Apple connector has a strange dot pitch (1.75mm), so careful measuring is inevitable. Cutting wide enough grooves on the as yet unprinted board to isolate the pin 1,2,4 and 5 areas will do. Scratch off the entire middle pin 3 area. This is a precise job, though not too hard. Next I will solder the upper and lower individual tiers together with a short piece of copper wire, in the same way join the outer and inner contact pairs and attach some 0.75 square mm (yes, I live in Europe!) speaker cable to the 1-5 pair and the 2-4 pair. Seal this off with glue and also shrink sleeve, preferably of the adhesive type.
- The connector described above can be used to be soldered to bare wires of a universal power supply with the right specs. To attach it to a PB 24.5V/ 2.65A PSU without cutting its cable, thus rendering it useless as a backup for the old Powerbooks, I suggest you use a female 2.5 mm stereo (AKA TRS) jack. Forget about the RCA like ring/sleeve: this is only a redundant mass contact/sleeving. One contact of the TRS is also used in combination with the RCA like ring/tube to run the (in the case of ACD use also superfluous) charge/ power led in the connector. Carefully determine polarity and pinning of the PSU with a multimeter once attached to the female TRS.
To be sure: http://pinouts.ru/Power/apple_tibookpower_pinout.shtml
Please warn me if any of my info turns out to be incorrect! In turn, I will keep you informed on my own 20" ACD repair as well.
Thanx again, and happy soldering!

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#19500 - 12/05/11 02:54 PM Re: looking for pinout for apple cinema display [Re: hexdiy]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
glad to have helped. That center pin is a current supply line a bit like the one tied on the usb ports, to inform the device how much current it is allowed to draw from the device. Devices that believe the source can't supply enough current will refuse to use the power source, as a safety.

that's where the "you can't charge this ipod from that usb port" message comes from. works the same on this adapter. the old white bricks for the older minis don't supply enough power to run the newer white minis for example. That large cinema brick appears to rule the roost for current supply however.

Since current is supplied on demand, there's no danger in attaching a bigger current source to a smaller device, you won't "blow it up".
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