Modifying a 12V SMPS for variable voltage.

I required a variable power supply for my lab test bench. But all the power supply which I saw in the market is a linear type. They have poor efficiency and dissipate more power. So I decided to modify a readily available 12V 10A SMPS in the metal cabinet to get the variable voltage. Although it already has a potentiometer to change the voltage that goes from 10.5 V to 14 V only.

The power and the voltage requirements were all favorable for me but the voltage was not. So I was only required to change the feedback loop components to get the variable voltage.

The feedback loop consists of a voltage divider which senses the output voltage and provides the error voltage to the controller. Now I replaced the feedback components with the diagram as shown.