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.)
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
- 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
- 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!