Powerbook G4 Power Connector Replacement
Posted on August 7, 2008
*Warning: screaminglight.com and all associated entities are not liable if you screw up while doing this. kthxbai
*Warning: This will probably (probably = actually) void your warranty. screaminglight.com is not liable for that either in any way shape or from.
*Warning: What you are about to do should only be undertaken by a competent person, not your pet monkey Guenter, even if he has a small hat.
*Warning: Make sure you read the FULL page BEFORE starting anything to confirm you know what you are getting into!
*Warning: By following the instructions below you release screaminglight.com and all related parties from any and all liability and damages as a result of this process. I can help you if you run into problems but I provide help at MY discretion.
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My Powerbook G4 power connector has been flaky for years. I’ve had the laptop since 2002; in that time I’ve gone through 4 power adapters. If you have a powerbook, you may be familiar with the symptoms: as soon as you look at the connector, your system is running on battery, not wall power. You fiddle with the connector, push on it, apply force in various directions, and eventually it reconnects. The problem is progressive, too: the first time, all it usually takes is turning the connector, but within 6 months you’re doing the "my laptop power connector cut off" dance – pushing on it, swearing, and generally making anyone who sees you wonder if you’ve lost your mind.
When my powerbook connector pulled this trick again this December, I decided enough was enough. At $79 per, those converters aren’t cheap – and the worst bit is, there’s nothing wrong with the electronics, it’s just a bad plug! I resolved to replace the connector in my laptop with a more robust plug – like the type every laptop manufacturer except Apple long ago decided was preferable.
Accordingly, I went to Radio Shack and picked up a coaxial DC power plug and matching panel-mount jack (I used size L). Cutting off the bad plug from the DC converter was easy, and soldering on the replacement wasn’t much harder – I soldered the cable shield conductor (COM) to the outer plug conductor, and the inner wire (V+, 30 VDC in this case) to the inner conductor. A bit of heat-shrink tubing finished the easy part of the project.
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Replacing the power jack on the laptop is a bit more strenuous. The first step is cracking the case and disassembling things until you can remove the DC-In / RJ-11 board. I suggest a guide from iFixIt or a similar site. Note to the wise: the iFixit Screw Guide is a life saver. There’s about 40 differently-sized screws you’ll need to keep track of.
The iFixIt guide calls for removing the entire logic board and heat sink to remove the RJ-11 board. I found that I could pry up the left side of the logic board enough to pull out the speaker assembly from under it without removing the entire main board and heat sink, which saves a considerable amount of effort. (I left the hard drive in the computer and the display attached too.) If you do pull the main board, get some heat sink compound from Radio Shack while you’re there – you’ll need to reapply it to the processor before reinstalling the board. Here’s a modified version of the iFixIt guide, showing only the parts you’ll need to remove.
Once you’ve done all that, you should have this board out of the case. (If you didn’t remove the main logic board, you may have to wiggle it free, but it’ll come out.) This is the DC-IN / Sound board.
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We’re concerned with the section of the board shown on the left here – the DC input jack. The goal of the exercise is to remove the Apple proprietary jack shown here and replace it with our generic jack. I broke out the DMM and, using the old plug, figured out the input pins.
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The most satisfying part of the whole project was removing this old jack. I decimated mine with wire cutters. After some (perhaps strictly unnecessary) rending of the old jack, I got it off the board in about 4 pieces. I clipped the old pins off close to the board.
Soldering short leads to the new jack allowed me to attach it to the board (center pin to V+, outside conductor to COM) so that the jack would fit into the same hole in the case the Apple jack used. A little wiggling fit the repaired DC IN board back into the computer, then I simply followed the iFixIt guide steps in reverse to reassemble my laptop. Before I put anything back together, I checked continuity from the proper pins of the male plug to the V+ and COM pins on the board with a multimeter, then checked voltage across those pins (again, on the DC-in board itself, above my solder joints) with the power adapter plugged in, just to make sure I’d wired everything properly and didn’t have a cold solder joint or a solder bridge short – hand-soldering leads to flat solder pads isn’t my idea of fun.
The new connector occupies almost exactly the same space as the old one. The only difference is that it sticks out from the case about 3/16", where the nut fits on, and that it doesn’t disconnect every time I give it a dirty look.
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EDIT: I have received some email about Vsense, the sense voltage that Apple puts on the tip of the original plug to tell the PowerBook what type of adapter it’s plugged into (65W, 45W, or Airline power – each type of adapter allows different functionality in the PowerBook in the original design). I did not include Vsense in my modified plug out of simple ignorance – I assumed that the tip (and the associated 400k resistor to ground) was used mostly to provide the light-up ring on the original plug. I have no idea where I got this assumption; I may have been delusional from lack of Laptop by then 
.
In any case, I have not modified my replacement plug since I learned about Vsense because I’ve had no need to. My PowerBook doesn’t seem to miss the input voltage; the charge timer has been more-or-less accurate (as accurate as it ever was, anyway), and the battery charges without any problem. The KISS principle seems to apply – if it works, don’t add “features”!
Jason
This must be one of the first Aluminum G4′s or a Titanium. With more recent G4′s (I have a 1.5GHz Al G4) it is not possible to remove the sound card without removing the heat sink, which implies removing the motherboard. So go ahead and do that, it makes removing the left speaker much easier.
@Paul – Mine is a 1.25GHz Aluminum Powerbook. I didn’t say I *recommended* getting the DC card out without removing the motherboard; I just said it was possible for me to do it.
GENERAL DISCLAIMER: If you try this and break your motherboard (or anything else), I take no responsibility. If you’re in this deep, you should know that it’s at your own risk. If you’re not willing to take the risk, pay someone who’s insured to do it. /DISCLAIMER
Hi
I’m going to attempt this project soon on my 12″ 1 ghz G4 Powerbook. Thanks for the excellent imformation. What gage wire (or other material) did you use for the short leads your soldered from the new jack to the board?
thanks
John
I used some solid copper breadboard wire I had handy for the connections – it was pretty thin, maybe 16 or 18 ga. max. On reflection, doing the math to figure out what gauge is sufficient might have been a good idea… Let’s see, 70W / 30V = 2.33A; this table shows that I should use a minimum of 18 ga. for power transmission, 26 ga. for chassis wiring, so I should be ok. The jumpers were less than an inch long.
The tip of my pwr spply just broke off into the jack! this is the 3 brick that has F’d up on me.. i am doing your conversion… i like to tinker and i have taken the computer completely apart just for fun. however, i am not too savy with wattages… i know that the pwrbk is 65w or 75w would it hurt my powerbook if i used a pc brick with the conversion? i think those are usually 120 or 150w
@J-Man: That sux. I pulled the broken-off tip from a friend’s adapter a few months ago. It wasn’t fun. My Dell AC adapter is 100W, I think; Powering the G4 from it won’t hurt the adapter, and as long as the adapter is putting out the right voltage (~28V DC according to my DMM), it shouldn’t hurt the laptop. Just make sure you get the pins connected correctly!
thats what my assumption was thanks jason.
just finished… 1hr and only $6 later… my mac works. thanks!
Awesome job. This works great just as written. Before I did this the Apple store wanted to charge $100 to replace the DC power board and already started preping me for a possible logic board replacement… $$$$$$$$$$$$$ or maybe we could interest you in our new model?
Hey jason, I had the same problem of the tip of the powersupply breaking off inside the DC-in port. How did you get your friends out? I have tried everything I can think of to get it out.
Steve, it wasn’t easy. I wound up taking the DC-in board out of the computer, putting a really small drill bit (like #44) into the Dremel (which I powered though a light switch dimmer, to get the RPMs down to about 500), and drilling a small hole through the piece of metal on the back of the DC jack. Then, I used the drill bit (with the power off) to push out the broken tip, and replaced the plug on the end of the cord with a standard 1/8″ phono plug from Radio Shack. I tried a bunch of other things before I drilled that hole; nothing was working. Even with the hole, it was really jammed in there; it wouldn’t have come out any other way.
I am about to try this method however the replacement jack for the board has three prongs and i only see two connections in the pic. Is the third attached at the bottom of the board?
@happy, the replacement jack I bought only had 2 conductors. If yours has a third, you could probably use it for Vsense; see the info at the bottom of the post, and check out the links:
http://developer.apple.com/ga/ga2001/ga1266.html and http://pinouts.ru/Power/apple_tibookpower_pinout.shtml If you’re using a 65W (or higher) power supply, you should put a 400k-ohm resistor between Vsense and ground in the new plug. Best of luck!
Trying this fix, cannot figure out how to solder the new plug on the power supply. Can you go into some detail for me on the easy part of this process?
Phil
Thanks for the info. I’ve had a hard time with my plug recently, i’m on my 4th adapter too. So far, the first one caught on fire, the second one melted, the third one was third-party and the plug broke off, and now i’m on another third-party one, and i said, “enough nonsense!” so I might be following your example soon.
My socket just broke last night about an hour after commenting, so I fixed my plug today following your advice. Only difference is my Radioshack didn’t have any L plugs so I used an N plug. I’m happy to report that it works better than before, in fact, better than when I bought it. On top of that, I don’t get the case buzz i was getting with the old adapter. I’m one happy customer. Thank you bunches for this advice!
[...] Powerbook G4 Power Connector Replacement : Screaming Light Studios [...]
If this works, I’ll be so grateful. My purchased generic jack also has 3 prongs. I understand the V(+) is the center prong, but I’m unsure if the middle or outside prong should be used to connect the COM – does anybody know how to determine this? Also, got excited and tore out the plastic ring protecting the original power – now using a metal jack, I’m facing grounding issues. I’m thinking a little felt or electrical tape(?) Thanks so much
@Kevin – How you wire the new jack is 100% up to you. Personally, I’d wire it with V+ on the center conductor of the jack and the new plug, and COM on the outside – that way, you don’t have to worry about insulating the jack from the case; attaching the grounded metal jack simply grounds the case, which is how it should be anyway. That’s how mine is wired; I also removed the plastic ring on the case and screwed the jack directly to the metal, although I’m not sure the photo shows that very well. You can ignore the middle pin if you want, or use it for Vsense with a resistor as mentioned; again, your choice. Best of luck with the repair!
@Phil – are you worried about polarity, or about the mechanics of removing and reattaching the plug? The polarity is up to you – just wire the plug and jack to match and you’re home free. The mechanics are pretty easy too – I just cut the old plug off completely, stripped back the wire a little, and attached the plug from Radio Shack. Personally, I wired the middle wire in the cable to the middle plug connector, and attached that jack conductor to V+; then I wired the cable shield to the outside conductor of the plug, and attached the corresponding jack conductor to COM. If you have a third conductor available, you can use it for Vsense as previously described (wire a resistor from that lead to COM), or you can leave both the jack and plug conductors unattached without hurting anything.
Wow—that was fun. The underside of the sound/DC board was horrific. The solder on the COM link had completely vaporized, leaving only a smear of soot. No wonder the battery had completely stopped charging.
There’s really not much fundamentally wrong with the design of Apple’s plug or jack. The blunder is that the only things anchoring the jack in place are five tiny blobs of solder! A few hits or tugs and those joints start to fail. That’s why this problem develops slowly: each knock loosens them a bit more, then the joints start to overheat, and eventually they fail altogether. When are engineers going to learn that solder is mechanically weak and not up to the task of holding down a connector that’s going to be subjected to daily push and pulls? Bolting or riveting an important connector in place is a basic I learned in the first few months of electronics hobbying. But that would add an extra dollar to the cost of your $2500 computer, and we couldn’t have that, could we?
I couldn’t find a size L connector around these parts. It isn’t even listed on RS’s web site. Could size N have been meant? Anyway, I ended up with a size M, which was a little too small to fit comfortably in the hole, so I needed washers. Couldn’t find suitable washers anywhere, so I cut 3 out of styrene sheet with a Dremel tool: two large ones, one for inside and one for outside, and one very narrow one that sits inside the hole and separates the jack from the hole’s inner edge. This also means my jack is properly insulated from the case. Using size M turned out to be a good thing because I wouldn’t have been able to cut an insert washer for size N; the fit would have been too tight. The plastic insert supplied by Apple won’t isolate most jacks from the case, so ripping it out and replacing it isn’t a bad idea. Allowing the jack to make electrical contact with the case, on the other hand, is a very bad idea.
I left out the PCMCIA cage during reassembly. Haven’t used PCMCIA for years, and none of the electronics stores around here even sell PCMCIA cards any more. It seems to be pretty much obsolete and I don’t expect to miss it. The big benefit is that there’ll be no need to disturb the logic board if there are any future problems with the DC board.
Kevin: It looks like the above posters didn’t understand your point. The third contact on the jack is a switched contact, used by some systems to tell when a plug is inserted. You don’t need it for this project, and I cut the third contact off so it wouldn’t get in the way. If you have any kind of multimeter, or even a battery, lamp, and wires, you can find out which contact is which by inserting a plug and testing to see which contact is still connected to the outside. The switched contact disconnects on insertion, while the COM contact remains connected. Failing that, if your jack is the same as mine (looks like the one in this picture: http://www.radioshack.com/product/index.jsp?productId=2102491) the switched prong is the one opposite the V+. The COM—the one you need to wire up—is the one between them.
Caveat: Different manufacturers may do it differently, so test it if you possibly can. Also, you can do it the other way if you like—V+ on the outside and COM in the center—but personally I’ve always stuck with the convention of having COM on the outside. It’s one less thing to worry about.
@Bob – Wow, that’s one heck of a comment! I’m so glad the process worked for you!
To answer your questions: In my jack, the problem wasn’t the solder joints from the jack to the board, it was that something about the connection was causing the insulation on the plug, between the tip and the middle conductor, to break down over time. Maybe it was a bad jack; maybe it’s a side effect of routing power over a connection designed for audio signals. Either way, there are obviously multiple methods of failure in this connection. I’ve not heard if the mag-safe connectors on the new MBPs are any better; I sure hope so!
I *think* the plug/jack combo I used was size L, but I’m not sure. It may well have been M or N. It may also have been something my local Radio Shack has had in stock since 1953 – I live in New Mexico, after all, land of electronic tinkerers.
Thank you for the clarification about the third pin Kevin was asking about. The connector I purchased didn’t have that pin; I was assuming that it was just a third conductor connection!
Thank you very much for your work.
Following your indications I was completely successful in changing the power connector on my PB G4 in a breeze!
After years of uncertainty in power now my PB is born again !
Thank you again.
Sandro
I had this problem on my 17″ 1GHz PowerBook. I got its RJ-11 board disassembly manual from iFixit.com; the steps are significantly different from those for the 15″.
I made a few modifications to the 17″ iFixit guide for this project:
* Step 14: It’s not necessary to disconnect the Bluetooth antenna cable; it’s long enough that you can just swing the Bluetooth board out of the way, leaving the antenna cable attached.
* Step 15: This step is unnecessary (disconnect the speaker cable from the sound board).
* Step 17: I couldn’t figure out how to disconnect the orange DC-In ribbon cable from the logic board, as the guide instructs. But it was easy to disconnect the cable at the other end (the DC-in board) by lifting the collar holding the cable in place.
* Step 19: The “rainbow” power cable that the guide refers to is all black on my laptop.
* Step 22: I needed to slide the DC-In board up as well as to the right in order to get it out.
I had to remove the old power jack from the DC-In board by breaking it apart with a slot-head screwdriver, needle-nose pliers, and a hacksaw. It was hard to get it apart without damaging the board it was on, but I couldn’t desolder all of its contacts at once.
I used a size N DC power plug and jack, RS part numbers 274-1583 and 274-1573, and they fit well, with no extra washers needed. I did have to remove the plastic collar that the Apple power jack slid into, using a thin screwdriver and needle-nose pliers. I broke off the unneeded third switched contact from the new jack so it wouldn’t get in the way, as recommended by Bob’s comment above.
It works! My PowerBook now charges while turned on and doesn’t emit a loud whine when plugged in.
The only serious side effect is that the USB port by the power jack stopped working, but I have a two-port USB2 PC Card so I don’t miss that built-in USB1 port. Also, it may be charging more slowly than before, because it thinks it has a 45W power supply plugged in, but that’s much better than not charging at all like it used to.
Is it possible for a person to follow these steps for a replacement DC input without basic electric knowledge?
@Jeff- “Possible” and “advisable” are not the same thing. While it may be possible to follow these steps and get it working even if you’ve never picked up a soldering iron before, it will take a fair amount of luck to avoid causing more damage than you fix. If you don’t know V+ from Common on a power supply, or what the difference between DC and AC is, I wouldn’t try it – I’d start with some very basic learn-to-solder kits. They don’t cost $3k to replace if you screw up. I’m not responsible if you do attempt the repair and fail – see the disclaimers at the bottom of the article.
[...] quite a bit on the web about this. One Apple Powerbook owner writes: If you have a powerbook, you may be familiar with the symptoms: as soon as you look at the [...]
Finished the project. I took my time with the disassembly. (2 evenings!)I stopped when I got tired, I didn’t want to do something stupid and break something. I did have one glitch. I broke the keyboard connector pins on the motherboard. I improvised the reassembly with success. Good instructions for fix: (http://www.laptoprepair101.com/laptop/2009/11/17/fix-broken-keyboard-connector-on-laptop-motherboard/) I got everything back together and is working like a champ! Love the new power connector. Works great! Plus, not giving the mac repair guys $250.00 is a bonus too! Thanks.
[...] After my PowerBook’s power connecter finally caved in, I decided I had to attempt a resucitation, using the using the handy guides from Fixit.com and Jason’s Screaming Light site. [...]
Jason,
(I did it on an acer box a year ago)
you’re the boss, man!
(maybe it’s already boring for you to read that;-) another success from Croatia, at this very moment I’m writing from my born-again powerbook G4 alu!
I must say that I had the same idea, (I already bought a standard connector) but I admit I was chicken to try it out like you did on a mac
big job!
thanks a lot!
The first failure has been posted – Freelance Unbound’s second pingback above indicates that, although it took all day to un/re-assemble the laptop, the repair was ultimately unsuccessful. I’m so sorry it didn’t work for you; I have a thousand questions – did you check the voltage across the pins directly on the board after you completed the solder joints? Did you let it charge for a good long time (~30 min) before powering it on? – but I know that, after pulling apart one of these laptops, the *last* thing I wanted to do, was to contemplate doing it again. If you decide to attempt it, drop a line; maybe I can help troubleshoot the problem.
I followed the steps and everything worked great. I was a bit overwhelmed at first with all the tiny connectors inside the computer. My USB on the power socket side stopped working also, so I took it back apart (most of the way) and disconnected and reconnected all the ribbon connectors and now everything works great.
I have that found the radio shack connectors break easily (the part connected to the power chord) so I switched my set up to us AV connectors (like the ones you use to plug in the back of a tuner/vcr…the red white and yellow ones). I took a male end and connected it to the chord and took the female and connected it to the board with a couple inches of wire to let the plug stick out of the computer. Sure, it dangles out there and looks a little silly, but it works and has cost me about $2 total. All I did was follow the instructions on here. Good luck everyone…you really have little to lose.
Do any of you know anyone in the Los Angeles/Long Beach area who would be able to do this?
great,man. i got G4 from a scrape store.They were going to hack it into plastic aluminium etc. I need to make a power source.apple here was costlier than in US.OK Ill keep you informed,Thanks a lot.
Hello,
I have just disassembled a powerbook G4 12″ which is slightly different then the 14″ you have written about.
The only thing i have a problem with now is that i dont know what soldering joints on the DC Board are V+, GRND, and VSENSE.
I could just leave Vsense i guess and switch polarity with the male connectoor if i soldered it in wrong.
But could someone help me?
One soldering point has a white triangle the other two are numbered 2 and 3.
there are 5 and 6 but they arent used in this guide so i guess they can be left empty.
I just tried this and broke my computer YOU OWE ME A NEW COMPUTER.
-j/k
Gonna try this soon. Hope I don’t fuck everything up. This page has been very helpful. Thank you for sharing this experience I really appreciate it.
btw I LOVE the very durable look you had on your jack after fixing it. that nut looks pretty cool… reminds me of a 1/4″ audio jack.
After going through every step of this at length, I gave up. I’m not an expert at soldering and I’m pretty sure I’m going to screw up. I do need to replace my power connector and I’d like to offer the opportunity for anyone to do this for me (for a reasonable price, of course). I’m located in the DC area, and can bring or mail the laptop to you. If anyone’s interested, I can be reached at phil@inbox.mailas.com
Let me know.
Thanks, Phil
There is a quick-fix for this, too- using a flashlight and a needle, you can reach inside the connector and pry up the second contact- the deeper and harder to reach tip contact. It’s not as solid a fix as changing the connector outright, but has lasted for over a year to keep my 12″ G4 alive and useful. I imagine doing this several times would fatigue the brass and make it snap off, but I’ve not had to do it again- yet!
I have just performed the procedure.
I now am very confident about opening a Power Book G4 apart. I had to pay £800 to have the screen replaced after an incident. Since then the power lead had to be replaced. The new one lost its stupid power connector so I set about putting in a 2.5mm standard plug and socket.
I thought I removed the old socket neatly with some fine snippers. Then I soldered wires to the V+ and Com locations. The plug and socket were then simple to solder.
To get the sound card lose, I removed the minimum screws but also the display hinge screws on the left. In this way it was easy to lever up the whole mother board and shift the sound card out.
All the connections are in place and I know the power supply is available. Just lick the tip of the pluc and you know it’s live. Unfortunately, the computer is not making use of the power supply.
Maybe I caused damage to the sound card when snipping off the old socket.
Maybe my soldering (with a 30 watt iron) created excess heat.
I now think a new sound card might solve the problem but I shall have to reinstate the old plug. Then it occured to me: why does the power lead feed the sound card? Why can’t the power lead simply charge the battery? Can you get a charger for the battery as you can with most other equipment?
Finally, can I extract the hard drive and retrieve it’s information if the whole Powerbook story is now over.
Fortunately, I have a MacBook Pro, so life goes on.
Could I borrow a charged battery from another power book user and download the hard drive content?
It was fun but I lost a couple of days.
Thanks for the ride.
Suffering the same fate with my powerbook aluminum g4 12″ and inspired by your blog, I just tore into mine. SInce mine has the 1.5 processor its a little different inside. I had to take out absolutely everything to get to the dc jack (heat sink, logic board, everything). Pictures here:
http://www.flickr.com/photos/52829626@N06/
Examining the dc input jack and the board I realized its very different than the one pictured in the blog here. Also I noticed the tip of the adapter had broken off inside the jack. I was able to get it out but it still appears to be broken. I believe the green light on the adapter should light up when plugged into it even when not attached to the computer. This does not work and the plug does not feel like its seated all the way. So I plan to replace the jack like other have done here however Im faced with a handful of problems
1. Since my jack and board are different I don’t know where to connect the voltage and ground.
2. Since my jack is broken Im not sure if I can effectively measure the continuity to determine where the voltage and common should be attached.
3. I don’t believe there is any way to experiment without potentially frying something.
What I know.
A) My Apple power adapter puts out just under 24volts and has a single wire with positive voltage surrounded by a web of fine wires that is the ground. Ive cut the tip off and everything still measures fine.
B) The male portion of the adapter had 3 sections on the tip and a sleeve around it. Assuming the sleeve is ground I measured the individual voltages on the tip. The first section on the tip measures almost 0 voltage, the second section (middle) measures almost 0 voltage and the last section (nearest to the main housing) measured just under 24v. I measured 2 adapters so I assume this is correct.
C) When plugged into the DC in jack I get no through voltage. It appears the adapter is not seated correctly and infact it appears that maybe one of the gold contacts inside is either missing or pushed toward the back.
D) When I put my Fluke meter in continuity mode I get continuity when touching the sleeve and the two outside pins on the jack (numbers 4 and 5 on the board). I assume this is ground. I also get continuity when touching pin 5 and 4 so they are connected for sure. When I stick the probe inside the female section of the jack I get cont going to all 3 tip contacts (TRIANGLE, 2 and 3 see picture). If however, I pull out the probe to where I guestimate where the positive part of the adapter would touch I only get continuity on pin #2.
E) The pins marked TRIANGLE, 2 and 3 all have specific areas on the board that they go to but nothing indicates which is supposed to be the positive voltage. None have continuity with each other without the probe plugged into the jack.
Because I do not have a working jack I don’t know what more I can do to decipher where the voltage and ground need to connect (though I suspect the ground should connect to pin 4 or 5). If someone out there can identify where I should tie into to supply voltage please let me know. Ive gone this far so I don’t want to stop now. If you can offer any assistance that would be super great.
Suggestions? Hints? Other resources I can look into to source the correct places to tie into? Does anyone have functioning dc in jack they can test? Does anyone have one of these apart, but working that they can measure voltages on? Can anyone read the bored well enough to simply know where to tie into. Ive exhausted my skill set and don’t know what else I can do without a working unit to test. I really need some help and it seems there are some smart folks here.
Please see pictures. Thanks for your help in advance.
@SG – I just took a look at the photos you posted. Your plug and mine look different when mounted on the board, but they have the same pins on them. Based on that, Pin 3 (the center conductor) should be your V+, and the triangle pin should be your Com (ground) pin. All of the Apple G4 power supplies use the same pinout – I often borrowed power supplies from friends and family with 12″ G4s when I was carrying mine around! I’m glad your board had markings on it; mine, as you can see, was totally without any kind of ID. I mentally tagged them center, left, and right while I was working on it. The larger, side pins on both boards, yours and mine, are just grounding the plug to the case – I ignored them.
Hey Jason, Thanks for your rapid reply!! In trying to work my head around the difference between your findings and mine I decided to take apart the jack entirely to see what contact went where. Inside there was a single bent contact on mine that would not allow the rca style jack to fully seat. Meaning the base ring of the jack (3rd from tip that actually measures voltage) did not make contact with the contact for pin #2. So I infer from this that #2 has to be the incoming voltage to the board?! Maybe Im missing something. In taking it all apart I found:
The tip (no voltage) goes to triangle on the board,
The middle section (no voltage) goes to #3
The ring closest to the base (24v) goes to #2.
The sleeve goes to pins 4 and 5 which is an isolated ground that does not touch the chassis
So though I can imagine the triangle possibly being common Im not sure why its not tied into the ground? And if that were the case I imagine the adapter would have a common wire, pos Voltage wire, and ground shield coming into it. But it only has voltage and ground? And unless conductor 2 and 3 have a circuit that opens after voltage is supplied I really cant imagine the voltage is supplied to pin 3? Maybe that supplies voltage to the light indicator that comes on the standard adapter tip? Your jack in your photos is distinctly different than mine though it still does have 3 pin outs at the end. It ties into the board in a different way and has what looks to be a resister connecting the middle and outside pin underneath. This might explain why supplying voltage to the middle pin would also work in your situation. Also since you did not shield the jacks ground from the chassis you have essentially taken the ground that normally goes to pin 4 and 5 and tied it into the chassis. This is obviously fine on your machine as it works, but my jacks ground was specifically shielded to prevent the sleeve from contacting the chassis.
Boy, I am almost more confused now. I completely understand your logic but Im still hesitant. It may indeed work but I don’t think thats how it was designed to work. I dont know if my board has any different issues that would make doing it the way you did cause problems. Does anyone have a working dc in for a g4 12″ 1.5 ghz that they can measure? Id feel better knowing where the voltage is going for sure. If I dont hear back Ill just go for it with my fingers crosses, but if someone can offer more insight please do.
Thanks for a great blog:)
@SG – Oh, my jack was also shielded from the case, which means either the case was grounded elsewhere, or was left ungrounded. If it was grounded elsewhere, another ground can’t hurt; if it wasn’t grounded, it dang sure should have been! (I have noticed that, since the mod, I don’t get static shocks from the case anymore, and that used to be a common occurrence…) Common and earth-ground are two different things in most electronic wiring; they may or may not be connected.
Pin 2 should be tied to pin 3 within the plug by a 400-ohm resistor, to provide Vsense (and tell the laptop which wattage power adapter is connected); as noted at the very bottom of the article, I omitted the connection out of ignorance, and never bothered to correct it – as you say, it works. If you think pin 2 should be V+, I don’t think you’ll fry anything if you try it that way, right or wrong – as long as you don’t reverse V+ and common, the other two aren’t as critical. (When I connected V+ and common backwards momentarily, the pitch and volume of the switching power supply’s hum changed – I pulled them quickly and didn’t do any lasting harm.)
Hey, can you confirm that in the 12″ powerbook the dc-in and the sound card are on the same board between the battery case and the hard drive? Thanks.
Paul
Hey Jason, I followed your guide here after having the same issues for more than a year and it worked beautifully! It’s so nice to have my old friendly mac back in top shape. Thanks so much for posting this and saving me 800 dollars! It did take me about 6 hours though.
Hi Jason!
Thanks for your guide! I finally got my old PB started again.
However I did connect a 390K resistor (I only have access to E12 series resistors) between GND and VSENSE. In System Profiler however, the adapter is recognized as a 45W not the 65W that it is.
Out of curiosity: what does your System Profiler report your adapter as?
If it says 65W I’ll open up the computer and toss out the resistor
/Daniel
Thanks! I just finished fixing my wife’s powerbook, it will make her day, as she’s been stuck using a lousy Dell replacement while I was fixing things.
In the end I didn’t put the PCMCIA slot back (never use it) and also removed the phone jack (also never used it, but also the power adapter I got from radio shack was too big for the original opening so had to put it where the modem jack was).
Initial scare when first powering up as it wouldn’t boot until the battery was 20% full? Maybe because I didn’t hook up the Vsense wire.
Also, airport wireless doesn’t work
It all looks hooked up properly. Maybe removing PCMCIA slot somehow affects things. Will have to make do with a USB wireless dongle.
Anyway, thanks again! I never would have attempted this w/o this site for help.
Hi Jason,
Thank you so much for this great guide. You encouraged me to replace the power connector in my 1.3 GHz G4 Alu (mid 2004).
• I was able to wiggle the sound card out without taking the mainboard out first; the only screw I took off from the mainboard is the one close to the bass speaker. I then had to lift the black plastic piece a little & very carefully in order to unscrew the PC-card slot.
• Breaking the plastic ring which separates the old jack from the case facilitates removing the sound card. Also, bending the case a little, very very little (!) to the outside makes it easier to get the other connectors (esp. modem, USB) out of the grey plastic rings and then remove the sound card.
From the comments above and my experience I guess that your guide is valid for the PowerBooks up to 1.33/1.5GHz (mid 2004). The next series might have little different design then.
– btw: I connected GND on the outside which connects to the case. I wouldn’t risk to connect the case to V+ as this *might* result in a short circuit.
Christian
@SG and Jason : I opened up a powerbook g4 12″, broke open the connector and found the following :-
The triangle connects to the ring (+24v), pin #3 connects to the tip and pin #2 connects to the middle ring (GND). Also, you can see that the PCB around the screw hole shows connectivity to pin #2 indicating that #2 is definitely the GND.
So according to me, the triangle is +24V and #2 GND. Also, the size of the PCB tracks connected to these pins is much larger than that connected to the pin #3. Kind of confirms that #3 takes lower current – and should be V sense.
Can either of you confirm this? If not – I’ll try this and post back.
I can confirm that the powerbook g4 12″ usses the following connections –
triangle – +24v
#2 – GND
My powerbook is working fine now.
i can confirm the last post. just did my powerbook g4 with the +24 connected to the triangle and the GRN at pin #2. thanks for all the info.
Has anyone contemplated upgrading the power connection to a intel-era “mag-safe” type power connection? It might be possible to accommodate one where the modem connection is.
I suppose one would need to find a source of genuine mac power connectors (maybe broken macbooks sold for parts on ebay), but it would be great to retrofit that technology to the g4.
I’m about to switch to my 4th power adapter and came across this great blog, and that just occurred to me. Does anyone know whether this would be possible?
Jason,
Just finished the procedure on a 12″ aluminum 1.5 ghz powerbook. It all went smoothly and the battery is charging fine but now my screen backlight does not work. I don’t know if I did something to cause this or if something burned out.
I went back in to make sure everything was reconnected and it all looks good.
Any Ideas??
Thanks
Mark
@Mark – I don’t have any ideas… the backlight on mine went out about a year after I did this mod; I still use the laptop, but have to use an external monitor with it. I looked into replacing the backlight, but it just wasn’t worth it for me – it’s a stay-at-home machine these days anyway, so the built-in screen was no big loss. I hear it’s not too difficult though, especially after the mod you just finished! (I was able to use a CFL spotlight in a clamp stand as a very temporary “backlight” to let me install a new HDD though!)
Help needed!!
As from my name, I’m from the UK and have a problem, I cannot find the same size connectors to adapt my broken power on my Powerbook G4 12″. What I can find is the following:
http://radioshackonline.co.uk/product.php?productId=425&categoryId=44
Will this be suitable for the conversion?
Thanks
(a quick response would be greatly appreciated as I use my Mac for my s/e work)
Just finished replacing the connector. Worked well on a 1.33Ghz Powerbook. Although I had replaced the HD before, I did not expect this to take so long. I had to take everything apart, including heatsink and logic board. This did take a few hours, including having to glue the sockets for the heat sink screws, which came loose in the process.
@Jase: I’ve also bought that socket to try a few. I am afraid that one doesn’t fit very well.
@jase
You can use whatever you want probably, just make sure that you clear the stuff in your way behind the jack in the computer and make sure that you get the appropriate plug to use in the socket. The bad part about the plug you have picked it is goes in the other way, try and find one with the nut on the other side. I just did this, what a nightmare… I didnt find this page till after tho, so I used a external plug just because it seemed like the thing to do and I was sick of messing with it.
[...] diy segment. i followed this guide to do it. laptop chargers (all chargers actually) are usually done in a particular way by the [...]
I just finished and turned on the G4, It came on with the start sound, but no screen. After awhile the screen came on for 5 seconds, but then went off. Pressing a key causes the screen to come on for 5 more seconds but it then goes off again. Any ideas?
so very cool.
I just spent the afternoon following your great directions, plug in my old powerbook after two years gathering dust in the closet and it started right up – amazing!
I now have a new Macbook Pro so after reading your tips I thought what do I have to loose, before I throw it away or sell for parts I might as well try.
and now i have a 2nd powerbook that works again! Now if it was only as fast as my Macbook Pro!
thanks a million – Brian