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macbook air a1466 820 3437 no power no… Hello i’m french sorry for my english . i have logic board 820 3437 no dommage liquid , no power no fan no green light. i changed dc-in magsafe . PP3V42_G3H 3.44v PPVRTC_G3H 0v PPBUS_G3H 8.24v PPDCIN_G3H 14.95v SMC_BC_ACOK 3.41v PP5V_S5 5.05 PP5V_S4RS3 0v PP3V3_S5 3.34v PPDCIN_G3H_ISOL 14.95v PPBUS_S5_HS_OTHER_ISNS 8.24v PPBUS_S5_HS_COMPUTING_ISNS 8.24 but U1900 and Y1905 are hot and PPVRTC_G3H 0v i remplaced u1900 and y1905 but always hot . U1900 is very hot I’m lost . I need your help thanks you very much
Something on PPVRTC_G3H line is being shorted to ground, likely a capacitor on that line if you have replaced the chip. You can check this by checking continuity on U1900. Check C1910 and any other capacitors on the way to the CPU (in schematic document, ctrl+F “PPVRTC_G3H”, to see any capacitors on this circuit). Try removing the capacitors on the line, see if a short is still there, and if not, it was one of the caps. If this doesn’t work, remove u1900 and check for a short on pin for PPVRTC_G3H. If there is still a short, it will be the CPU.
