Strange Magsafe Behavior

I have a mid 2010 Intel Core i7 15" Macbook Pro. My original magsafe charger was left in a hotel so I purchased another. Now it won't charge. So I purchased a brand new one 2 weeks ago. It won't charge.

BUT...the previous version of the magsafe (the "t" version) will charge poerfectly. I borowed one from work as an experierment.

I have reset the SMU. Cleaned the connections. Nothing. Nada.

Why would the T-style magsafe charge but the newest L-shaped ones not?

Anyone? Anyone? Bueller? Bueller?