replaced midframe and digitizer/lcd no image, only backlightpleaseread

i replaced the midframe and the lcd,digitizer combo. I have done this a thousand times with no issues.

it is an iphone 4 gsm

the backlight comes on but the lcd doesn't show anything, my old lcd worked before so i changed it back and hooked it up and still nothing with the old working lcd connected. I then used a third one and still nothing.

the connectors look fine, i hooked and unhooked em 20 times same with the battery with time in between.

i tried the hard reboot and still nothing

i get no response out of the digitizer but my phone will do voice control

any info will help please, like i said i hooked and looked alot and seen a million people online only say that. please let me know something. thank you