“A key component of the Apple Watch made by one of two suppliers was found to be defective, prompting Apple Inc. to limit the availability of the highly anticipated new product, according to people familiar with the matter,” Daisuke Wakabayashi and Lorraine Luk report for The Wall Street Journal.

“The part involved is the so-called taptic engine, designed by Apple to produce the sensation of being tapped on the wrist. After mass production began in February, reliability testing revealed that some taptic engines supplied by AAC Technologies Holdings Inc., of Shenzhen, China, started to break down over time, the people familiar with the matter said,” Wakabayashi and Luk report. “One of those people said Apple scrapped some completed watches as a result.”

“Apple doesn’t plan a recall, because there’s no indication that Apple shipped any watches with the defective part to customers,” Wakabayashi and Luk report. “Taptic engines produced by a second supplier, Japan’s Nidec Corp., didn’t experience the same problem, the people said. Apple has moved nearly all of its production of the component to Nidec, these people said, but it may take time for Nidec to increase its production.”

Read more in the full article here.

MacDailyNews Take: This may explain why some early reviewers have been describing the Taptic Engine as “very subtle.” We experienced no such thing with our Watches and couldn’t understand those characterizations. These early reviewers may have received Watches with defective Taptic Engines.

Regardless, this certainly goes a long way towards explaining why the initial Watch supply is so massively out of whack with the demand that we, and certainly Apple, and anybody else with a brain have expected since the device was unveiled last September.

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Apple Watch set to lift fortunes of Hong Kong component supplier AAC – December 22, 2014