Saturday, May 10, 2008

Repairing an 85W Magsafe Power Adapter

A little different post today - not about leadership, process, or some great new technology. It's about fixing something yourself; fixing things sometimes pleases me almost as much as creating things. After you read this, go get a copy of Sam Martin's How to Mow The Lawn.

I love my Macbook Pro. I like the idea of the Magsafe adapter, but I'm not happy with the fact that it's single sourced. I guess iGo hasn't reached a licensing agreement with Apple for the technology, because it isn't as complex as you might think. Since it's expensive, I carried around the one adapter I have. That is ... until the cord wore out - the wrapping and unwrapping of the magsafe side eventually wore out the cable. When I took it to the Apple store I learned it wasn't repairable (don't get me started on sustainability concerns). I bought another adapter, and was hoping I might be able to fix the one I have so I don't have to repeat this problem.

I was expecting a lot of complexity in that cable, since it has numerous pins at the laptop end, and operates the little orange/green LED somehow. However, this is a no brainer to fix electrically, it's really a packaging problem, because the case was not designed to be disassembled (or re-assembled). So I thought I'd document what I did so others can keep these little guys out of the landfill, and maybe save $60 in the process. The one I repaired was the older, larger adapter.

The case appears to be a press fit with some glue. I couldn't pry it open with a screwdriver or putty knife, and since I wasn't expecting this to be so successful, I very quickly pulled out the Dremel tool cutting wheel. I arbitrarily chose the side with the metal post -- which turns out to be the best place to start. There is a heat sink behind this side that won't get hurt if you cut into it a little bit. I cut into it and started to pry.

I was doing pretty well - the sides opened up pretty easily, but was afraid to crack the case so decided to cut a little bit into the opposite side.

At this point I was a little exuberant and let the corner pieces fall out when I finally got the case open. Not a big deal but pay attention to how they fit. There are three pieces per corner where the cord wrapper device is.

This is where the real surprise hit me. There are only two wires in the coaxial cable. The white one goes down the middle and the black one is the wrapper. I was expecting the little cord protector to just slide off, but it won't.

So rather than unsolder the wires and resolder the cable to the board, I decided to use a razor knife and cut away the cord protector. This turned out to be pretty easy. After stripping away the insulation I soldered the wires to each other, and wrapped in electrician's tape (I was too lazy to find the heat shrink tubing - but that is the correct way to do it - get some at Radio Shack).

I then tested the beast before physically reassembling the case. Be careful here - I felt a slight shock when I touched the metal parts. It worked.

I superglued the case together and added hot glue where I had a large gap from the first cut, as well as around the hole where the cord comes out. I clamped it together in a vise to let it dry. Here I apparently didn't have one of the corner pieces in completely right and I broke a pin off. I used a palm sander to clean up the case exterior (and learned, by the way, that hot glue doesn't sand very well - keep it neat and remove excess with a razor. Not beautiful, and probably no longer rugged enough for travel, but it is safe and it works.

Level of Difficulty: Low
Time: 30 minutes if you don't break anything
Tools: soldering iron, Dremel with cutting wheel, #10 and #16 wirestrippers, hot glue gun, sander, vise (or clamps or rubber bands), screwdriver or putty knife, Box Cutter or Xacto
Supplies: Solder, Electrical Tape (or Heat Shrink Tubing), hot glue, superglue