No power supply came with my Memory Toy. It has a 9v icon on the face but says nothing about what mA to use for it. I plugged in every 9v i had(300,500,700) and nothing works. It actually lights up with the 700 but no effect. There must be a battery inside because when I disconnect the power cords it works fine. I tried to open the back plate but the screws are kinda cheap and one of them stripped on me. Should I send this back? Or am I just overlooking something totally obvious?

Frustratedly yours
Jim