1999 The Beatles Yellow Submarine Lava Lamp

This is a 1999 vintage Beatles Yellow Submarine Lava Lamp. I got it from a relative and shipped it home. When I followed directions to set it up after multiple days, the lamp worked, but the lava is not flowing. There are online sites describing how to change out the liquid and wax, but I didn't do that. This is a great collectable for a Beatles fan.