macbook pro retina 820-3332-a no backlight

[highpulse]

well , open the machine and found the F9700 damaged , not making continuity , so replaced , but still the same . cheked the components around , backlight drivers and the fets , and found something dam weird , pin 1 of lvds connector i GOT 55.1 VOLTS .. (yes 55.1v ...wtf how is that possible )
so i notice backlight driver u9701 pin 21 BKL_FB is 20.5 volts (not sure if its normal) but altough , after D9701 Katode size i got 55.1 volts , but on the anode side i got 12.6volts (what seems really normal to me ) but katode size being 55.1 not normal .. i think there is a problem with backlight driver ic , so would be nice having some outher opinions .

thk in advance

[highpulse]

Re: macbook pro retina 820-3332-a no backlight

ok so after further investigation , pins 1 should be realy around 50 to 56v so here all good , i got the enable lcd also with 5 volts , there is image on the screen also .but simple no backlight , but having 55v on pin 1 should give power to light , but therefore cheking the backlight driver IC it has 6 output returns bkl_isen1 to isen6 (6 returns , all the returns are 0 volts . now it can be backlight driver damaged or the screen assembly is not ok .

[alekk89]

Re: macbook pro retina 820-3332-a no backlight

It should be the screen, replace the hinge that holds the lvds cable and it should be fine.