Conversation so far:
What happened in the early years of The Smashing Pumpkins?
In the early years The Smashing Pumpkins was just Billy Corgan and James Iha.
What happened after Billy Corgan and James Iha met for The Smashing Pumpkins?
After that Billy Corgan and James Iha added D'arcy Wretzky and Jimmy Chamberlin.
Did Billy Corgan, James Iha, D'arcy Wretzky, and Jimmy Chamberlin of the Smashing Pumpkins start working on music together?
Billy Corgan, James Iha, D'arcy Wretzky, and Jimmy Chamberlin began making music together.
Did the Smashing Pumpkins ever perform the music they wrote?
On October 5, 1988, the complete The Smashing Pumpkins took the stage for the first time at the Cabaret Metro.
Did the first performance of The Smashing Pumpkins go well?
Why did Corgan and D'arcy Wretzky have  problems with the merits of the band?
What happened after the conflict over the merits of The Smashing Pumpkins?
After this show, Cabaret Metro owner Joe Shanahan agreed to book The Smashing Pumpkins on the condition that they replace the drum machine.

Question: Who was the replacement?
Self-contained rewrite: Who replaced the drum machine for the Smashing Pumpkins?