Ipad will not start. Apple logo comes and goes

See this Apple article: If your iPad won't turn on or is frozen

If your iPad won't turn on or is frozen - Apple Support

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Contact Apple Support to set up service.

Try also this -> Force restart iPad -> Force restart iPad – Apple Support (UK)

KentRP Said:

"Ipad will not start. Apple logo comes and goes: My ipad is fully changed. When you start up, the apple logo appears and disappears after 3-4 seconds. It does not respond to a hard restart."

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Go Here: If your iPad is Stuck On the Apple Logo - Apple Support

Your iPad is exhibiting symptoms consistent with a fully discharged or failed battery.

As a first step, connect your iPad to its Power Adapter and allow the iPad to charge undisturbed overnight. Then, while still connected to external power, try to perform a forced-restart:

• On an iPad with a Home button: Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
• On other iPad models: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top button. When the Apple logo appears, release the button.

If the iPad does not restart, these support pages may help with troubleshooting battery and charging issues:

Charge and monitor the iPad battery - Apple Support

If your iPad won't charge – Apple Support

Troubleshooting generally requires substitution of the Power Adapter and cable for another known-good item. Be aware that most models of iPad require a Power Adapter rated at 12W or greater to reliably charge. 5W Power Adapters intended for older models of iPhone are inadequate to charge an iPad; if the iPad charges at all, charging will be very slow.

Be aware that many computer USB ports cannot source sufficient power to charge an iPad. Unless explicitly designed for charging connected devices, computer USB ports are typically limited to 0.5-1A @5V (i.e., 2.5-5.0W).

If you continue to experience difficulties when using an appropriate Power Adapter of 12W or greater, you might be best advised to seek assistance directly from from Apple Support. You can contact the Support Team using the Get Support link at top-right of this page. Alternatively, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:

https://apps.apple.com/gb/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad, Power Adapter and cable(s):

Genius Bar Reservation and Apple Support Options - Apple