Yamaha TW-E3C True Wireless Earbuds (Red) - Manual (Page 43)

The product cannot be charged
(
Your computer is not turned on (when charging from your computer).
Turn the power of your computer on, and then charge this product.
(
You may have been using a USB power cable other than the one included with this product.
Use the included USB power cable to make sure the product correctly charges.
(
The earbuds and the charging connectors in the charging case may not be coming into contact.
The earbuds will not charge if they are not properly seated in the charging case. Use your fingertips to
lightly slide the earbuds from side to side and store them in the proper position within their storage
compartments, and make sure that the earbud indicators are lit. Also note that the earbuds may not
charge correctly if there is any dust or dirt on the surfaces where the earbuds and the charging
connectors on the charging case come into contact. Use a dry and soft cloth, a cotton swab or similar
material to wipe these surfaces off before charging.
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Troubleshooting > The product cannot be charged