[captainanakata]

so i got this mbp, and i lost my adapter
the baterys long scence died to the point where the power level indicator wont lite up
so instead of buying a new one for 80 bucks somewhere i thought i should go about building my own

i took a piece of pci slot cover and cut it out and folded it so it fit and stuck in the magsafe port, then i hotglued pins touching the 4 outside pins

but then i ran into this problem

i know the mbp runs on 18.5v
but idk if its dc, ac, and its polarity

most likley its like this
either
{+-(led)-+}
or
{-+(led)+-}

if someone could take a voltimeter to thier magsafe and post thier results it would be much apreciated

all i need to do is charge this thing up every night

thanks in advance

[ghporter]

It is quite possible that with the 8 pins involved that some of them are to tell the charger that it's connected-it may not be possible to see what the pinout voltages are because they may not be present with the connector disconnected. Since I'm STILL waiting for my MBP (not because of Apple, but through a third party that's also paying for it), I can't tell you whether this is true.

[ibook_steve]

Here's some really good advice and I seriously hope you heed it:

Do not try to build your own power adaptor!!!

Batteries and power adaptors are two things that you should not compromise. If you're willing to spend the time and effort to try to build a substandard power adaptor that may or may not work, let alone could be an electrical or fire hazard, I think you can find the cash to buy a new power adaptor to replace the one that you really should not have lost in the first place.

Again, please, for the love of someone's house or apartment, do not do this!

Steve

[sahnapiranha]

According to my sources:

The MagSafe connector consists of a magnet and an attraction plate. The magnet is placed within the computer. The attraction plate is part of the DC plug on the power adapter.

The DC plug consists of five pins. Each pin is spring loaded. The center pin is a sense pin. This center pin must make contact with the computer before power is applied. Power is carried on the remaining four pins. The outer pins are positive terminals, the inner pair are the return paths.

The pin pairs to either side of the sense pin are redundant. As such, the plug can be put in two ways. To support this design, the power LED is on both side of the connector. The behavior of the LED is the same as before, amber for charging the battery, green for supplying power, but not to charge the battery.

[spice003]

how do you loose a power adapter that big?

[captainanakata]

its easyto loose one, i put it somewhere and idk where it is now

i def have the skills to make a power adapter (ie 18.5v transformer that suplies less than the maximum amperage/dosent overheat and damage..)
fire hazards arent a problem, im not guna start using it like a regular adapter, i just need to recharg it

sahnapiranha, does the adapter use a digital signal on the center pin, and is it required? (is it analog) does the macbook care if it has a digital signal or is that just a saftey in the powersuply?

ibook steve, thankyou for your concern but ive totally done worse , this is safe dont worry :-p

can anyone else confirm this pinout?
thanks to everyone

[tonton]

Originally Posted by spice003

how do you loose a power adapter that big?

Originally Posted by captainanakata

its easyto loose one, i put it somewhere and idk where it is now

I know I'm a "looser" but God dam it it's spelled "lose"!

This mistake in spelling is seriously spreading because people see it spelled incorrectly on the internet and think it's correct.

L-O-S-E = lose, rhymes with shoes, means to misplace or be defeated.
L-O-O-S-E = loose, rhymes with juice, means not tight, or free/escaped.
L-O-S-E-R = loser, rhymes with boozer, means someone who has been defeated, or as an insult to mean someone who has failed.
L-O-O-S-E-R = looser, means more loose/less tight fitting, i.e. "My ex-girlfriend's **** was looser than Karl Rove's morals".

Back on topic, making your own power supply is a bad idea. There are circuits in the charger that among other things, help to prevent overcharging and deterioration of your battery's health. Remember, a proper $80 adapter is still cheaper than a new $120 battery, or worse...

[MaxPower2k3]

Originally Posted by tonton

Back on topic, making your own power supply is a bad idea. There are circuits in the charger that among other things, help to prevent overcharging and deterioration of your battery's health. Remember, a proper $80 adapter is still cheaper than a new $120 battery, or worse...

If that happens, he can always just build himself a new battery. All you need is a bunch of AAs and some tape.

Really, though, I wouldn't try this. Like tonton said, there's battery charging circuits that protect the battery (and you), and on the offhand chance that you do mess something up (short out a pin or whatever), Apple will likely require the faulty power adapter to perform the repair under warranty. Since you don't have that, you may end up having to pay the full cost of the repair (well over the $80 a new adapter would cost). And if they suspect that this was your fault, or find out about your charger-buildin' antics, that warranty will be gone for good.


...Or, if you really are as good as you say, start mass-producing these things and undercut Apple on the cost. You'd be the first to market with a third-party Magsafe adapter.

[ghporter]

tonton, thanks for your post. I try not to let my blood pressure get tweaked by people's "loose" spellings, but sometimes I can't help it. Your well-thought-out post (rantish for emphasis; cool!) helped me not bust a gasket.

captainanakata, buy a NEW CHARGER. By Murphy's Law the original will turn up after you've charged your battery sufficiently to use the computer. As long as the original has not fallen down the bottomless well in your back yard, or been vaporized by aliens, or even absconded with by persons unknown, it will turn up. And you WILL be sorry for trying to build your own charger, if for no other reason than the time and effort you went to will seem wasted. I have over 25 years of hands-on electronics experience with a specialty in power systems, and I would not attempt this.

[spice003]

here is one hella cheap $42 buy it now and good feedback , 1 month warraty $14.99 shipping, thats the cheapest you will find.

eBay: APPLE 85W MacBook Pro Portable Power Adapter MA357LL/A (item 280028222183 end time Oct-13-06 23:40:34 PDT)

[Oneota]

I don't trust anyone with spelling that horrible to do something as complicated as making a safe, functional MagSafe power adapter.


Buy a new one. Seriously.

[SSharon]

Just for reference Handbook of hardware pinouts, cables schemes and connectors layouts @ pinouts.ru
they don't have the magsafe though, but perhaps it can help for some other dangerous project you are working on.

[captainanakata]

ive already checked so many places for that pinout.
thank you for the spelling and decision advice to all who contributed

it appears that there are few engineers here. its really quite simple if you think about it

heres my logic, (oh by the way your ability to care about how well a post on a forum is spelled has absolutley no connection with ones other skills)
anyway, the power adapter has 2 main functions when equipt with the magsafe
1, step current suply up and down as the machine needs it to increase efficiency.
2, if there is no conection sensed dont supply any power

all li-ion batterys have the charger control built in, (yes for thoes of you who are anal, maby some ancient japaneese designed li-ion batery has an external charger, whatever...)

but for the most part the above is true

second, the power dosent NEED to be steped up or down, it isnt anything important, the macbook has enough power control in it to be safe within limits.

so if i suply the proper voltage with enough power the result should be one of 2 things

1. it charges till it cant charge no more
or
2. the macbook is redundant and dosent accept it because of the sense pin

anyway the chances of me geting enough balls goin to plug something made of information that hasnt been confirmed into my precious macbook pro are pretty slim.

however if i do and it dosent explode then ill tell ya all about it

EDIT*- about my warranty, yeahhhh, its already farrr gone, ive open'd the thing up 3 times to repair the crappy heatsink grease, the thing would overheat and shutdown while i was on aim. then i accidentally broke off a resistor between the main apc chip and somethign else, had to resolder that... then i took it apart again cause my solder fell off. its hard soldering things the size of this ( ~ ). not to mention trying to get that damn display inverter to stfu, i gave up on that one a while ago tho.

[outthere]

quite fun, things like this should happen more often
more plz