Edited sentence: A funny coincidence happened with a bunch of Selectic terminals that were ordered by Wang Inc.But a few months later, each and every terminal started misbehaving.But after a while the golf-ball positioning cams would wear down a little bit.But if the spring was missing, the golf ball would tend to flop around and misprint text.It turned out that all of those Selectrics, by "pure chance" was shipped with a small but important spring missing.Many customers, thinking Wang equipment was unreliable, returned their systems or did not order additional ones.No problem, the spring was designed to keep the cams in contact even with a little wear.The Selectric would work okay without the spring for some time.The terminals, as delivered to Wang, seemed to work just fine.This almost bankrupted Wang.Wang Inc.Wang bought the terminals as part of their first word processing system, which would compete directly with IBM's word processing MT/ST.had to send out repair persons to each customer to repair the printers