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Wednesday, April 26, 2006

Fixing a Powerbook G4 hinge

We have an old Powerbook G4 at work that has a broken hinge that I am attempting to repair. Why bother repairing such an easily replaced part? When the replacement part costs more than the value of the laptop, that's why bother. I'm serious, a pair of these hinges run over a hundred dollars on eBay, and several hundred dollars direct from Apple. This for a part that was poorly designed and has a history of breaking. The actual hinge part is so hard to twist I can't move it with my fingers, I have to use a pliers. All that torque is transferred through a tiny little arm.

If you notice where the break was, it's in pretty much the worst place possible. An important part of the repair is loosening the tension on the hinge because it's pretty much impossible to repair this well enough to withstand the original forces. By loosening the hinge our repair only has to hold the screen in the right place and doesn't have to deal with all that torque, so it will last a lot longer. The other hinge supplies enough force to keep the display from flopping around.

To try and give the hinge a fighting chance I bent a small piece of metal around the joint. This wraps the joint in a sort of splint and gives the epoxy a lot more to hold on to. This is also a very important piece, it would be worthless without it. The best glue for this job is probably J-B Weld, a two part epoxy designed to join metal together. I didn't have any of that available so I used some gas tank repair epoxy instead. It's pretty similar to J-B Weld except that it is designed to fix gas tank leaks.

Here it is after mixing the epoxy and squishing everything together. It seems fairly rigid but I'll have to wait until tomorrow to test it. If this doesn't work I'll get some actual J-B Weld and try the same thing using that. If the J-B Weld doesn't work then I'm pretty much screwed unless I happen to find the best welder in the world and he wants to do me a favor because that's the only other option I can think of to try and fix this hinge.

So much for quality Apple hardware.

Update: Well I didn't even get to see how well the repair would stand up, I managed to break the hinge into three pieces before I could get it into the laptop. Turns out there is a channel in the hinge that is there to allow room for the power wires on the display. The little sleeve I made covered over part of that groove so I was trying to cut a little piece of it out. My hand slipped and busted the top of the hinge right on the hole that attaches it to the display. Good news is that it broke in a different spot so at least the repair was somewhat successful. Bad news is we'll have to come up with another use for the laptop without the screen.


  • were I have see three of the G4 have the hinges get fixed on them

    By Anonymous Dave, at 1:33 PM CDT  

  • How did you loosen the tension on the hinge? I have broken the left hinge and I think Eboky would hold it up in th escreen where it broke but I can't move it without piiars like you described. Any tips?

    By Blogger Wes, at 9:58 AM CDT  

  • There's a notch on the hinge pin that you need to rotate to line up with the open space on the hinge bracket. Once it's lined up you can lightly hammer the hinge pin out of the bracket. Then I used a vice-grip to hold onto the flat part of the bracket and used a flat screwdriver to pry up on the curved part. The curved part is what grips the pin so you just need to bend it out a bit so it doesn't grip as tightly.

    By Blogger Tom, at 10:09 AM CDT  

  • Thanks Tom... I'll give it a try. This is the second Powerbook we've had this issue with.

    By Blogger Wes, at 10:35 AM CDT  

  • Hello. Another lost soul with a broken ti-hinge here. I just wonder how the ... did you get the hinge out of the display-case????

    By Anonymous Johan of Sweden, at 4:04 PM CST  

  • There were 4 screws on the side if I remember correctly. The sides are sort of glued together so just pull on them carefully and they'll come apart.

    By Blogger Tom, at 7:29 PM CST  

  • Hello, I am new on this but i ahve a doubt you might want to help me on this: yesterday my baby boy fall down on my G4 titanium and the left side of the notebook lac i think brooke.. I mean the case where the lcd is have a rectangular hole and there is a thing that moves the lcd up nad down to open and close the monitor that does not go up and down even with the dtrongest force... I do not know how to fix this. I rang the Apple and they told me that they need to replace all the display with LCD included!!!! Crazy my LCD is perfect!! WQell I need some help on this and hope you can help me out thanks!!

    By Anonymous Anonymous, at 11:55 AM CDT  

  • Sounds like the latch is broken. Pull the LCD apart and see if that's what it is. You can probably buy a replacement latch on eBay.

    By Blogger TomTheGeek, at 12:30 PM CDT  

  • have resolved my broken hinges by using the display from a used working G4 bought on ebay for £40, also now got a spare HDD and DVD drive, airport card, memory, mother board and keyboard

    By Anonymous Anonymous, at 1:49 PM CDT  

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