how to cheak 5s touch screen ic ??? plz help urgent

The customer brought an iPhone 5s with no sim problem I opened then phone and cleared the board put back started the phone firs it had a touch screen freez a little I opened I thought my be flex problem but it works for some time then stopped working at all changed the full original LCD but the same touch not work is there any to measure the voltage to see if its ices problems tanx

via Welcome to gsm-tips http://ift.tt/1CRqnJn