The Definition of ASB is blurry and varies from person to person. Some would define it as direct intervention of supernatural forces. Others cry"ASB!" when seeing a merely improbable result. To the point when they see any military victory that isn't just a bloody grind, but has a bit of finesse in it, such as Falais or battle of France as an ASB.
Let's say we have to postpone invention of transistor for a dozen months. Non-lethal infection like flu could do the trick. John Bardeen, William Shockley and Walter Brattain worked in the same office, probably long hours. If one catches the bug he could easily infect others. Time it right and the whole project would be shelved, because the would do something else while catching up after sick leave. Of course another team, (in another lab?) could come up with something similar.
To remove it further out, one has to delay scientific underlay describing the effect. Julius Edgar Lilienfeld who patented first transistor in twenties could be killed in political turmoil before leaving for USA. That would give us a few years before somebody do the same research, and somebody with enough practical skills builds a working example and markets it.
To make POD further out, we have to remove Max Planck. He was Lilienfield's mentor, and lied foundations of his work. Let’s say that he contracted tuberculosis instead of his first wife, passing away in first decade of twentieth century. Tuberculosis wasn't called wasting disease without reason. With it Planck would have either a much shorter, or much more unproductive life. His removal would make TTL physics somewhat unrecognisable. Other people would discover various phenomena and name them differently. You may not have atomic bomb in 1945.