Controlling a motor with a pi and TB6612


I’m trying to control a 12v worm drive motor using the TB6612 motor with set up shown in the following link.

I’ve checked and checked and all my wiring is correct. I can attach the motor direct to a 12V power source and that works. I’ve checked the output from all my pi pins using an LED and resistor.

I run the code as seen in the link and nothing at all happens. I’ve played around with my own code also so AIN1 is high. AIN2 is low. PWMA is high. STBY is low.

Any thoughts what could be wrong? Could the TB6612 be faulty? How could I test this?

Many thanks.