No display Not recognize by iTunes After Repair

I was going to check the LCD and forgot to turn off the iphone before taking LCD From logic Board . returned every thing back but iphone doesn’t start , iTune not recognize it , I used all methods to reset but no chance Did I fry the Logic board by not turning it off before taking apart? can this be fix? thank you

I got it today Form repair shop . they told me that Motherboard was effected and they change some IC on the Board , i don't know whats that , but its working fine , i opened the phone and its same motherboard and same LCD . i don't know what they did actually