Apple Magsafe 85 watt power adapter - cord replacement

[Agent24]

I was given one of these to fix - and you guessed it - the cord is broken (surprise, surprise!)

Looks like you can get the cords on eBay, although considering the way these adapters are glued shut I fail to see how they could be a standard spare part from Apple, in which case I suspect the authenticity of them.

Anyone bought a Magsafe replacement cord from eBay? Does it work? I expect they do, since the feedback history on the sellers show people who bought them to be happy.

In any case, that all matters not if I can't get the thing opened without damage anyway, so I decided to work on that first.


Now, most people seem to open these with a hammer and chisel or some other horrible method causing gross disfigurement (shocking for an Apple product, of course!) so I figured I'd try something different.

See the attached photos for how I opened the case. (some force was still needed to open, but it was a lot less than otherwise, and tool marks were kept to a minimum)


Reassembly could be done with more glue (but in better locations) or just duct tape etc which would allow for future repairs without a big fuss when opening it again.

[Agent24]

Re: Apple Magsafe 85 watt power adapter - cord replacement

Well, I received the replacement cord from eBay today. It looks very similar to the original but a bit cheaper. The cable is also not as flexible as the Apple one, but maybe that's a good thing.

I will do the replacement soon and post on how it goes. Should be fairly simple. At least Apple appear to use decent capacitors in this thing!

[b700029]

Re: Apple Magsafe 85 watt power adapter - cord replacement

Curious to see some pictures of the inside.

There's also a lack of load tests done on them... will it really do 85W?

[Agent24]

Re: Apple Magsafe 85 watt power adapter - cord replacement

I'll do my best to get some more interesting photos, but the AC input socket is still glued to one half of the case and I don't really want to cause any extra damage trying to pry it out as well.

A load test would certainly be interesting but I doubt I have the equipment to do it 'properly' - besides it's not mine so would rather not try to blow it up!

I have no doubt though that whatever its power capacity is, it's enough for the job Apple designed it for.

[Agent24]

Re: Apple Magsafe 85 watt power adapter - cord replacement

New cord installed today, all seems to be working OK.

Took some photos showing the installation and some closeup of the adapter board.

Didn't open it further. Capacitors all seem to be Rubycon ZLH which is nice though.

New cord was a bit lax on the insulation though, needed a liberal dose of heatshrink.

Adapter was taped back together after testing on the laptop, hence no photos (but I'm sure you can imagine it!)

[shadow]

Re: Apple Magsafe 85 watt power adapter - cord replacement

Looks like you did a nice clean job of that!

[momaka]

Re: Apple Magsafe 85 watt power adapter - cord replacement

I'm glad this thread surfaced. About 2 weeks ago, I found a 60W MagSafe power adapter in the trash can next to a Radio Shack (lol!). Mine had a damaged cord as well that was just a few centimeters from the tip of the plug. After cutting away the damaged cord, I checked the output of the power adapter and it only gave 0.45v. Checked output for short circuit, but all I get is climbing resistance, indicating that the output capacitors are charging.
So, it looks like I'll have to open mine as well. I like the procedures you used. Maybe I'll cut mine open as well rather than hammer the living crap out of it like I do with other adapters.

By the way, who's the maker of your adapter? On mine, it says Samsung.

[Agent24]

Re: Apple Magsafe 85 watt power adapter - cord replacement

Sorry, I never took note of the manufacturer. It's back with its owner now so can't check easily.

This model outputs 6.5v without load, but when connected to the laptop they ramp up to 19v (I think) - there's some extra circuitry in the plug for changing the charging light and maybe control the voltage as well.

Edit: Just looked at the eBay auction for the cord I bought, they said it was for 85 and 60 watt versions - so yours would probably have the same voltage control feature.

[momaka]

Re: Apple Magsafe 85 watt power adapter - cord replacement

Sorry, I never took note of the manufacturer. It's back with its owner now so can't check easily.

That's okay. I was just hoping that mine would have bad caps since it exhibits the typical start-up cap issue. But if it has the same quality caps as yours, then it probably isn't.

This model outputs 6.5v without load, but when connected to the laptop they ramp up to 19v (I think) - there's some extra circuitry in the plug for changing the charging light and maybe control the voltage as well.

I certainly hope not, since I was planning on using this adapter for powering a set of speakers and a few other electronics at the same time.
Then again, I wouldn't be surprised if Apple designed such a stupid feature.
I did try putting a load on it, though, but it didn't seem to matter - it still acts dead (maybe because it is).

Anyways, I guess we will see if there really is such a circuit when I investigate into it a bit more later this week. Most likely I'll cut apart both the plug and the adapter. I really don't like how Apple electronics are sealed. Mr. Dremel will be happy to help, though .

[Agent24]

Re: Apple Magsafe 85 watt power adapter - cord replacement

http://en.wikipedia.org/wiki/MagSafe#Pinout may prove useful.

http://www.flickr.com/photos/dnhosho...265267/detail/ photos of the magsafe plug

http://appliedprocrastination.blogsp...sassembly.html maybe interesting also

[rogfanther]

Re: Apple Magsafe 85 watt power adapter - cord replacement

It really stays at 6.5 until it is connected Had the misfortune of trying to repair the plug of one here. The plug is not an example of good engineering, but the owner had his share of guilt. All of his hardware ( three notebooks ) had signals of abuse.

From what I saw, the middle pin in the plug controls the voltage.