digitizer n ot working after replacement

Hello everyone, i got into my hands a ipad 4th generation from another shop that came in for digitizer replacement that stop working after a new one was installed i asked the tech if he used metallic tweezers or screw driver to disconnect the cables from the connector, he said yes so i would know where to start looking since he already check connectors and tried other new digitizers.

im new in micro soldering and i like to get deep into board level repair and most (80%) i find the problem (hopping to get better 95% at least)

i found out the following: not voltage in U3101, R3107, R3120

i followed the voltage supply to the following chips and replaced them but no luck: U300, U3007, U3009, U3010 and the digitizer driver IC U3101

all of those ICs have not voltage, if someone can help me find the problem i will appreciate it, thanks