Use a known-working, MFi-certified Apple cable and wall adapter. Cheap, non-certified cables often damage the internal charging IC.
Keep holding both for at least 10–15 seconds until the Apple logo appears. 2. Check Charging Components iphone-6-no-power-solution-100-working
Often, the phone is powered on but "frozen" with a black screen. A force restart can jumpstart the system. Use a known-working, MFi-certified Apple cable and wall
Plug it in for at least 30–60 minutes before attempting another force restart. Use a known-working
Go to product viewer dialog for this item. that won't power on, start with simple software and external hardware resets before moving to advanced board-level repairs.