I seem to go through an awful lot of MacBook Pro power supplies and was wondering what other people's experience is in that regard.

It's not that the connector or cable fails which typically seems to be the case, it's just that suddenly the power supply no longer charges the Mac.

I have five MacBook pros in the family right now, the power supplies on all of them end up with the same problem after a couple of years - they just stop charging the battery.
The light on the little connector at the Mac turns green when I plug the power supply into the Mac indicating there is voltage but I assume no current flow, but then the LED never turns orange even if the battery s partially discharged.
I get a new power supply from Apple - that works fine on any of these Macs for a while - then the same thing after maybe a year or two; haven't really kept a track of that.

Now I actually have a power supply that had quit, as in only showed a green LED even with a partially discharged battery, but then after three days decided to work again.

The power adapter design of those 85 watt supplies is really marginal.

no issue with mine (85w that came with an i5 MBP) on a white unibody. I'm keeping the original 60w as a travel only adapter..

btw, if you are having issues with all the time.. i think it might be something with your grid power.

Do you have it plugged on a power surge protector?

I doubt it's a grid power issue, the problem is really the secondary.

But I don't usually plug these supplies into outlets with surge protectors. That's a bit difficult if one is travelling.

I expect that the unit itself would have some surge protection built in - I'm going to open one of the defective ones up when I get some time to see what kind of switching supply is inside.

You can buy little surge protectors that are little more than a small 1 or two plug three prong brick. I think even Belkin and similar companies make these! All my Apple laptop power supplies have worked quite a long time.

The only issues I've had was with the old white ones and the cord frayed on me. I still have it somewhere but its a 60w one and I'm a little hesitant to use it with my 15" MBP because its "should" use the 80w ones that i have.

The 85W adapters IME get quite warm, so if they are not in a place where they can cool properly they can burn themselves out.

Also, of course, it's helpful to put all adapters like these (Mac, iPhone, portables) on a UPS (uninterruptible power supply) when you're at home.

I doubt it's a grid power issue, the problem is really the secondary.

But I don't usually plug these supplies into outlets with surge protectors. That's a bit difficult if one is travelling.

I expect that the unit itself would have some surge protection built in - I'm going to open one of the defective ones up when I get some time to see what kind of switching supply is inside.

You should get one of those Belkin travel size 3 plug surge protectors.

My apple 60w magsafe is made by delta electronics, but i can't check my 85w right now.. it's plugged it and in use. It should be made by the same manufacturer, and have no built-in surge protection..

I was about to take the defective unit apart but decided to measure the secondary output voltage first to have a reference point.
Turns out that the outer two pins on the magsafe connector were somehow pushed back into the connector so they probably don't even make contact with the connector in the MacBook.

I'll see if I can fix that but this may mean the electronics in the supply are not defective after all.

The 85W adapters IME get quite warm, so if they are not in a place where they can cool properly they can burn themselves out.

Also, of course, it's helpful to put all adapters like these (Mac, iPhone, portables) on a UPS (uninterruptible power supply) when you're at home.Yup

Also I think there is a thermal switch inside.

I have had one quit

let it cool then unplugged from te wall and replugged and it started again.
I too go through them but I'm hard on them and do get into overheat situations.

Pins will stick and metal stuff get in the pins on portable as it's very magnetic.

I had the very first Intel MBP and two or three Powerbooks before them. I have had new MBPs every second year since. the latest being Dec of 2011. Not one 85W charge unit has ever failed. Am I just lucky, or am I closer to the norm since it seems to be an issue with few on ehMac, or they do not respond to this thread? Just saying. I did set my MBP on a cord last year and push it back on the table which stripped about six inches of the insulation to bare wire as it rolled the wire from the small cord with the mag adapter on the end. A quick wrap with electrician's tape solved that issue and it too continues to perform normally.

I have never noticed the 85W, or even the old Apple 60W power supplies to run warm - assuming they were being used with appropriate MB models, but Apple's design of the connectors used, and especially their strain relief design sure could use some improvement, even if the power cord is looped before coiling up and especially when any travelling is concerned.

I have my son's 85W unit here to replace the wiring connection to the MBP due to the power cord getting frayed and becoming unreliable, all due to poor design.

And all such access repairs seem to be a real PITA!!!

i've never had problems with my magsafe connectors..Though, i pull them from the plug, not the wire. It must make a difference.

Are all of your MB Pro's having this issue or just one or two of them? Have you tried moving the cords to different systems? Maybe try number the cords and machines and rotate them record which cords/systems that are having problems... this should help isolate where the problem is. As other posters have mentioned, it could be the system and not the cord.

I also agree... the Belkin travel surge protectors are awesome! here's a link: Belkin Travel Surge Protector with Hidden Swivel Plug F9H220-TVL (http://www.belkin.com/IWCatProductPage.process?Product_Id=182400)

It's the power supplies that have the issue, not the MacBook Pros.

Because I have a umber of macBook Pros here in Montreal I can check the "defective" power supplies with all of them and verify that it is the supply and not the Mac itself.

But I also have MacBook Pros in Belleville and in Toronto, so I doubt it's the power grid.

On the latest power adapter that quit, it may just be the two contacts of the Magsafe connector that got pushed back somehow and don't make contact anymore. So maybe nothing else is wrong at all.
The two previous ones I took back to Apple and had them replaced under warranty - never really looked at them closer to see what might have been wrong. Apple just replaced them without any hassles.

This latest one where the two outer pins are pushed back is well out of warranty. I opened the MagSafe connector up which was very easy and straight forward but I can't really get to the two pins to see if I can fix those.

When Googling for a fix for my son's MBP power supply with its semi-working broken over flexed cable, I noticed some sites were selling just the magsafe connector for a replacement. Either for the MBP connector or the cable connector. The price wasn't much as I recall.

Sorry I don't have the links.

Strange...mine is 5 years old now and still going strong (touch wood). It's been tripped over (popping the MagSafe connector out) umpteen times, accidentally stepped on, accidentally dropped and is pretty scratched up, but it's still working fine.

I've had to replace the power adapters on Powerbooks, but never yet on either my MacBook Pro (5 yrs old) or my son's MacBook (3 years old).

krs: wait a minute... are you saying that you actually unplug your cable/2 prong connector everytime you pack up for travel?

krs: wait a minute... are you saying that you actually unplug your cable/2 prong connector everytime you pack up for travel?

You mean the Apple proprietary connector between the AC power cord and the actual switching supply?
No, I don't.
There is never a problem there.

What happens is that the adapter decides to no longer charge the MacBook.
There is actually no visible physical damage anywhere that I ever noticed, no frayed cords or anything like that.

On the latest defective AC adapter I noticed that the two outside pins of the MagSafe connector that plugs into the MacBook were pushed all the way back and probably no longer make contact with the connector on the MacBook

http://upload.wikimedia.org/wikipedia/commons/thumb/5/55/MagSafe1.jpg/250px-MagSafe1.jpg

That would explain why this one no longer works - a purely mechanical problem.

http://upload.wikimedia.org/wikipedia/commons/thumb/5/55/MagSafe1.jpg/250px-MagSafe1.jpg[/IMG]

That would explain why this one no longer works - a purely mechanical problem.

For stuck down pins on the MagSafe connector, many have fixed the problem with a small spray of WD-40 and a small push implement and maybe needle nose pliers to move the pins in and out and get the spring loaded pins moving again.

Just don't apply any strong side force as they are easily bent, and oh yes, unplug the AC power!! ;)