The doubler DOES WORK. It's just the fact that if the output is low and has ripple, it is due to the 150u. This type of circuit was used in old back-and-white TV's as the transformer needed less turns on the secondary and by using two 200u electrolytics with low peak voltage ratings, you could get a good power supply up and running at a lower cost. The only thing was the need for a final filter capacitor to remove the ripple. If this capacitor was dry, the output voltage sagged and ripple was introduced. This seems to be exactly the fault with this circuit.