So, turn up your speakers / volume and have a listen. This is why I can't run the lamp for more than 15 or 20 minutes at a time, this pump issue gets maddening.
So, two options:
#1 Call lava lamp and see if they have a replacement pump which we know they won't
#2 Get a normal fish tank air pump, and extend the air tube through a nicely drilled hole in the back bottom of the base to the external fish tank air pump and enjoy.
By the way, I had to remove the round felt pad, which is easily replaced with some clear rubber bump on feet.
The rest is easy the lamp can be serviced from the bottom. At least the pump and LED circuit board.
If anyone wants more detailed photos of the innards let me know and I will post them.