Did Ronald Wayne ever disclose his reasons for leaving the company so early?
From the Ronald Wayne's Wikipedia page:


  Wayne received a 10% stake in Apple. Less than two weeks later, on April 12, 1976 he relinquished his equity for US$800. Legally, all members of a partnership are personally responsible for any debts incurred by any partner; unlike Jobs and Wozniak, then 21 and 25, Wayne had personal assets that potential creditors could seize. The failure of a slot machine company he had started five years earlier also contributed to his decision to exit the partnership.


Here's an interview by Steve Wozniak, where he describes situation leading to Wayne's exit.