Did I kill my voltage regulator?

[MGaddict]

I'm trying to get an old power supply working. It's outputting a wopping .2v on the 5v rail. There are 2 voltage regulators, lm7912ct and an lm7905ct.
I was trying to figure out how to test them and i found some examples for 7805 regulators and they demonstrated putting 7-27v into the input and you should get 5v on the output.
Seems simple enough.
Being a negative voltage regulator, I made some assumptions and I'm trying trying to figure out if killed this thing or it was already dead and likely the cause of my issue....
I used an ATX power supply to supply -12v to the 7905. The thing got hotter than heck immediately and had nothing on the output.
So... Did I screw up using -12v or was that right and this thing was already dead?
I'm going to order a replacement but before I try to test the 7912, I'd like to know if I screwed that up.

[langwadt]

Beware that the pinout of 78xx and 79xx is not the same

[MGaddict]

DOPE!!!
So, um, ya. About that...
I can still hope that it was already the problem i guess.
Stupid, stupid, stupid. I guess this is how we learn right?

[Zenith]

You also need a load on the output when testing those three terminal regulators. It need not be much, just enough to draw a few mA, but I've found that just using only a DMM (typically 10MegOhm input resistance) can produce strange results, especially if the regulator is faulty.