A new Mag Safe problem **HELP**

Grant

Grant

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I am at a friend's place.
His Mag Safe power supply has gone belly-up.
The green LED comes on but the laptop does not power on.
Tried using my power supply, his laptop powers up immediately.
Tried using his one on my laptop - nothing - just green LED.

He has a number other power supply units for other devices, one of which is a HP power supply.
It's a match in terms of output - 85w, 18.5v, 4.7A - the same as the unit for the MBP

Could this be used in an emergency ?

**edit
I have checked this power supply using a multi-meter, it's values are true.
 
Last edited:
I have extended my Mag Safe lead, the one from the charger to the laptop, it is only x2 wires...I used 2 core flex.
So, if you cut the lead near the charger, and connect to the HP charger's charge lead with the correct polarity I can't see a problem, but the I may be missing something.
I charge my 13" MBPR with the 65 W and 85 W chargers and no issues.
Good luck, but on your head be it.
 
D tj said:
I have extended my Mag Safe lead, the one from the charger to the laptop, it is only x2 wires...I used 2 core flex.
So, if you cut the lead near the charger, and connect to the HP charger's charge lead with the correct polarity I can't see a problem, but the I may be missing something.
I charge my 13" MBPR with the 65 W and 85 W chargers and no issues.
Good luck, but on your head be it.
Click to expand...

I have pulled apart both a mag safe connector as well as the actual charger.
If you test the mag save connector with a multi meter you get a low voltage (around 6v) from the pins.
It's my understanding that when you start the MBP it sends a signal (possibly through the centre pin on the mag safe) to the charger to now deliver the full voltage. The charger itself then "starts up".

With the HP charger I referred to, I suspect the 18v is always live, as opposed to the Apple which only delivers 6v until such time as the MBP call for full power.

I believe the 85v charger used for the 15" MBP's will work on the 13" units who's charger is 60v, but the charger from the 13" MBP will not power the 15" MBP
 
Check your insurance on the laptop 1st, then try, and report back, photos or video of the event a bonus!!:-)
 
I personally, would avoid this at all costs. Just go buy a new charger instead of potentially damaging a machine worth a lot more than some charger.
 
Tander said:
I personally, would avoid this at all costs. Just go buy a new charger instead of potentially damaging a machine worth a lot more than some charger.
Click to expand...

I agree - foolish to risk it IMO.
 
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