Finding Thevenin Equivalent with Dependent Source

[Matt O]

Homework Statement

I am trying to find the Thevenin Equivalent of this circuit

Homework Equations

Using KCL and node voltage

The Attempt at a Solution

I found the open circuit voltage for the thevenin voltage so far by the mesh current method, and now I am trying to find the closed circuit current. When I connect the short from A to B, that shorts out the resistor so there are two loops left. Now I'm confused at this step. There are only two nodes in the circuit left, and anywhere I try to write KCL or KVL equations I just get 0 = 0. How do I proceed forward?

 

[gneill]

If you have shorted AB then what is the potential across AB? How about the potential across the 50 k resistor?