Did my Power Supply unit burn itself?

they're going to make you buy a new one, but why not ask anyway? maybe you'll get lucky

It never hurts to ask:

http://support.apple.com/kb/TS4127

Do you know which end to hold a soldering iron?

Standard death of a Mac power supply.

If Apple doesn't exchange that for you, don't discard it:

You can repair it if you know how to apply cable end sleeves/ferrules (and have the crimping pliers for that).
Carefully cut off the rubber hose close to the case (without damaging the cable inside), isolate the two stranded cables, put on end sleeves, do the same with the cable (noting which is which), and wire them together with screw terminals. Liberally apply electrical tape so it doesn't come apart (you can wrap around the rabbit ears to provide some stability). Works like new

When did you buy your MBA exactly? If you don't have AppleCare, the standard 1-year Apple warranty is over. But you can file a claim with your credit card if you're still within 2 years of your purchase date. Otherwise, see what Apple says. At worst, you'll have to buy a new charger. At best, they'll swap it out for free.

4r Power Plug Longevity suggest stowage this way:

Same thing happened to me, apple store demanded £50 for a replacement, um no. They didn't have any serial numbers or anything from me yet, so I told them where they could stick their power adapter, got back in the car. Arrived at regents street to smiling apple store employees and a free replacement psu.

You *might* be lucky.

lucasfer899 said:

£50

Click to expand...

If you really have to buy a new one:

http://www.tomtop.com/45w-replaceme...and-13-inch-macbook-air-14-5v-3-1a-c1655.html

(See the column "Related Products" if you need a different wattage.)

Of course, as with all Chinese power adapters, it might kill you, but so far it hasn't killed me.

checkitout said:

but so far it hasn't killed me.

Click to expand...

If it does, how do we know?

checkitout said:

If you really have to buy a new one:

http://www.tomtop.com/45w-replaceme...and-13-inch-macbook-air-14-5v-3-1a-c1655.html

(See the column "Related Products" if you need a different wattage.)

Of course, as with all Chinese power adapters, it might kill you, but so far it hasn't killed me.

Click to expand...

Several friends have used similar replacements, and have woken up to a ruined battery in their £1500 laptop.