Dude its not going to work without optocoupler... The IC requires a feedback voltage to make any corrections as required if the voltage goes up or down...
Most PSU do have optocoupler no days it also used for seperation the primery section from the secondary incase of high voltage spikes.
So either you need to install an optocoupler in your PS or find a PS that has one on board.
The ATX PSU i bought has 3 instead of one.