Apple iPhone 4S Back light ok but no Display problem repair troubleshooting.
1st: Re-solder all LCD connector pins! Measure voltages with LCD connected also replace C76.
2nd: impedance (set multimeter to beep/diode then RED probe to GND and BLACK to component) on each leg on J4 connector.
1st: Re-solder all LCD connector pins! Measure voltages with LCD connected also replace C76.
