The cassettes are from Microman not Diaclone. And I hate to be the bearer of bad news, but that toy appears to be a fake. According to the Transformers Variations site it's from a KO Microman line called "Transistor Robots."
It's not a fake toy, it's a real toy. And to me it doesn't matter if was once Diaclone, Microman, Machine Man or Barbie. He's now a proud member of the Decepticon army named Buzzbeak.