Apple iphone 7
About a year ago I replaced the damaged screen of my iphone 7. Apart from having to instal a virtual home button, the repair went well and I have used the phone since without problem. recently my phone will not switch on and none of the suggseted reset options have any effect.
When I plug into the charger, after a few seconds the screen illuminates in white and a black apple logo appears in the centre. It stays lit for five seconds and then goes blank for 10secs. - then it repeats the same sequence. When the charging cable is removed the phone returns to its completely unresponsive state.
I would be grateful for any possible diagnosis and suggestions for repair.