Mag Safe power adapter
I need to buy one of these for my 09 2.5 MBP
Review this Apple T/N to ID your systems need: Find the right power adapter and cable for your Mac notebook
Ideally, order your charger from Apple or from an authorized reseller. There are a lot of bogus chargers which will hurt you and your system. Here's the Apple web site: MacBook power adapters
Here's a useful reference on giving your MagSafe & system the needed TLC: Apple Portables: Troubleshooting MagSafe adapters
Hopefully, these will sway you on why you don't want a fake charger:
The MagSafe 2 85Watt Power Adapter is ONLY compatible with "slim" notebooks (MacBook Air, MacBook Pro Retina) circa 2013 and newer (excluding the 2015 MacBook and 2016 MBP)..
If you need an adapter for a 2009 MacBook Pro (which is a Unibody, non Retina model), you'll have to look for a Magsafe 1 adapter.
Do not purchase a used one, lots of self-appointed technicians are purchasing damages adapters and swapping cables with counterfeit parts. Probably not the best thing to say on iFixit, but I'd rather have a fully original adapter.
Just google a YouTube video on how to open... I used electrical pliers and the supply popped open with NO damage at all to the case. It took about 2 mins to open 1 min to soldered the new cable in and 5 mins to put the case back together correctly and super glue and clamp the case for drying. The soldering is easy if you have basic experience. Suggest testing before you glue up... but really this is hard to mess up and it will work and look like brand new for a fraction of the price of a new power supply.
My experience is that it is the cable ends that go first. Right at the mag safe or where it enters the power supply. The replacement cable can be purchased for $6. For that price, it is worth the effort to repair.
They are so easy to fix - providing you are prepared to attack the casing with a hack saw! Yes, it is glued shut!!
The faults I have encountered is with the startup and output caps. When replacing, make sure the caps are rated at 105 deg C.