Contribution d'origine par : zzz ,
Are you sure that's the right 820 number? I can't find any retinas with that. 820-3787 or 820-3662 are the ones for late 2013. Hopefully this is 3787 because 3662 has nothing in terms of schematics. No diode mode measurements with power running through, it will let the smoke out! Measure voltage on pin 1 of LCD connector with it on. 0v, 12.6v, or something higher? 0v means something is gone completely, 12.6v means something is there but the circuit just isn't boosting.