What voltage should magsafe dc adapter check at?

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MacBook Core 2 Duo

Model A1181: 1.83, 2, 2.1, 2.13, 2.16, 2.2, or 2.4 GHz Core 2 Duo processor

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JoshuaK @joshuak39275

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Publicada: 27 de fev de 2012

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What voltage should magsafe dc adapter check at?

If I were to use a multimeter to check voltage on a magsafe dc jack, what reading should I get? Also, if anyone can pinpoint in a picture what point I need to actually check on the dc in. I have an a1181 model macbook. My problem is that the computer will not power up at all, even bridging the power solders. When I check the power solders though, I do get a reading of voltage as I do on many other parts of the board. I wanted to check the magsafe dc in to make sure it wasn't starting up because of a bad magsafe dc in.

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Now that I have though about it after I posted that, when plugged in it will charge the battery, I tried booting with the battery only and it still does not work. I'm at a loss, there are no signs of damage to the logic board at all.

27 de fev de 2012 por JoshuaK

Have you searched using the troubleshoot boot problem macbook tag to see a list of diagnosis steps. e.g. Will it boot to an optical drive? Has this unit been dropped or wet? What makes you think this is a charging issue, not a cable or HD problem?

27 de fev de 2012 por originalmachead

The unit gets no power at all, no noises, no fan spin-ups, no optical drive noise whatsoever. It is possible that it has been dropped or had liquid damage, I have not been with it 100% of the time, however there is no apparent drop or liquid damage, all of the liquid sensors are still white on the computer. I've tried to boot with no ODD attached as well as no HDD and no ram, still gets no power. It was just weird to me that I was still getting a current throughout different parts of the board, including the power pinouts, but it would not give me any signs of life when trying to start.

28 de fev de 2012 por JoshuaK

Oh and I have used to known working Magsafe power cords. They both will turn bright green when plugged in, they both charge the battery while it is in the computer, computer still will not boot.

28 de fev de 2012 por JoshuaK

I have similar problem. i tried to measure voltage in my power supply ( i have this model http://hardware.be/power-supply/dell/x14... and it shows that everything ia okay! But time to time it stops work. Could you tell me any advices, please!

10 de fev de 2016 por Scott Waschlerner

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originalmachead @originalmachead

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The MagSafe connector pins are palindromic, allowing for the adapter to be inserted in two opposite orientations. The first and second pins on each side of the tiny central pin have continuity with their mirror pins.

* The inner large pins are V+ (16.5 VDC). Measuring with no load will give 6.86 VDC; the full 16.5 V is provided to the proper load.

* The outer large pins are Ground.

* The tiny center pin is a Charge Control pin that assists with changing the LED color, and also assists with switching the adapter off. No power will be output from any of the other pins until contact is made with the center Charge Control pin. This pin is also used to transfer additional Information, such as the powertype and serialnumber of the powersupply.

The rectangular metal shroud surrounding the pins has no electrical function. Rather it acts as shielding for the electrical pins and a ferrous attractor for the magnet in the laptop.

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pin out is on the right: http://en.wikipedia.org/wiki/MagSafe

28 de fev de 2012 por mayer

+ Your answer is correct for the 65 watt magsafe, which is the one that came with and normally used for the A1181. On the 85 watt adapter the voltage on the inner large pins is 18.5 VDC. The 85 watt magsafe will work with the A1181, though it is more expensive.

28 de fev de 2012 por ABCellars

It doesn't matter what wattage adapter this is for to me as the pinout is the same which is all I wanted to know so thanks.

23 de out de 2015 por phill

Know of any reason why I keep going through Magsafes with only a few uses? I leave them plugged in and only use maybe 8 times a year to test water damaged MacBooks on occasion. Even if I use a customers Magsafe my outlets will kill the Magsafe. Everything else in my outlets work just fine and never had any issues ever. Magsafes keep dying. Volts are reading under 1V.

12 de jan de 2016 por Tony Tone

Some information in this answer is incorrect. Power does output the V+ pins even without center pin contact. With no center pin contact, a MacBook will receive power but will not charge. See link.

http://apple.stackexchange.com/questions...

8 de fev de 2016 por markallenhowell

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Now that I have though about it after I posted that, when plugged in it will charge the battery, I tried booting with the battery only and it still does not work. I'm at a loss, there are no signs of damage to the logic board at all. — JoshuaK
Have you searched using the troubleshoot boot problem macbook tag to see a list of diagnosis steps. e.g. Will it boot to an optical drive? Has this unit been dropped or wet? What makes you think this is a charging issue, not a cable or HD problem? — originalmachead
The unit gets no power at all, no noises, no fan spin-ups, no optical drive noise whatsoever. It is possible that it has been dropped or had liquid damage, I have not been with it 100% of the time, however there is no apparent drop or liquid damage, all of the liquid sensors are still white on the computer. I've tried to boot with no ODD attached as well as no HDD and no ram, still gets no power. It was just weird to me that I was still getting a current throughout different parts of the board, including the power pinouts, but it would not give me any signs of life when trying to start. — JoshuaK
Oh and I have used to known working Magsafe power cords. They both will turn bright green when plugged in, they both charge the battery while it is in the computer, computer still will not boot. — JoshuaK
I have similar problem. i tried to measure voltage in my power supply ( i have this model http://hardware.be/power-supply/dell/x14... and it shows that everything ia okay! But time to time it stops work. Could you tell me any advices, please! — Scott Waschlerner
pin out is on the right: http://en.wikipedia.org/wiki/MagSafe — mayer
+ Your answer is correct for the 65 watt magsafe, which is the one that came with and normally used for the A1181. On the 85 watt adapter the voltage on the inner large pins is 18.5 VDC. The 85 watt magsafe will work with the A1181, though it is more expensive. — ABCellars
It doesn't matter what wattage adapter this is for to me as the pinout is the same which is all I wanted to know so thanks. — phill
Know of any reason why I keep going through Magsafes with only a few uses? I leave them plugged in and only use maybe 8 times a year to test water damaged MacBooks on occasion. Even if I use a customers Magsafe my outlets will kill the Magsafe. Everything else in my outlets work just fine and never had any issues ever. Magsafes keep dying. Volts are reading under 1V. — Tony Tone
Some information in this answer is incorrect. Power does output the V+ pins even without center pin contact. With no center pin contact, a MacBook will receive power but will not charge. See link.

http://apple.stackexchange.com/questions... — markallenhowell

Adrian Chamorro @adrianchamorro Reputação: 1 · Answer 1 · 2014-07-03T08:05:46-07:00

Adrian Chamorro @adrianchamorro

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Publicada: 3 de jul de 2014

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What voltage reading should you get if measured directly from the power converter or from the cord? I assume the power supply is plugged to the wall but not to the computer. I want to know if the power supply itself works or if it is damaged.

Thank you

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MacBook Core 2 Duo

What voltage should magsafe dc adapter check at?

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