Plug in the power source, current reading on the ammeter is normal this time. Wait for the logic board to cool for several minutes, then connect the I/O Board to the logic board. Run diode mode measurement of F7140, it reads ‘0’ on the Multimeter, which is normal. So the fault might be related to C7371.ĭisconnect the power supply, replace C7371 and F7140 with a new one in turn. And touch the logic board with one hand, capacitor C7371 next to the CPU is hot. Current reading on the ammeter rises to 2.622A. Solder the supply wire to Pin 2 of F7140, then supply a 2V voltage with an external power source. Judging by this, F7140 has been burnt out. Reads ‘OL’ on the Multimeter, which is infinite value. Judging by this, the loading of PPBUS_G3H is short for grounding. Continue to run diode mode measurement of Pin 1 and Pin 2 on F7140, the measured value of Pin 1 is 131, which is normal the measured value of Pin 2 is 2, which is abnormal. PPBUS_G3H is fulfilled with the help of L7130 by way of F7140. Locate the exact position of R5430 on the board with bitmap, the run voltage measurement of Pin 2 on R5430, the measured value is 0.879V, which is abnormal. PPBUS_S5_HS_OTHER_ISNS, the rail-related to Pin VIN of U7501 is converted from PPBUS_G3 H with the help of R5430. (Locate the exact position of C7500 on the board with bitmap and confirm it by running voltage measurement of Pin 1.) The measured value is 0.878V, which is abnormal. Then check the working condition of U7501 with the circuit diagram.įirst, check whether the input voltage of Pin VIN on U7501 is normal. Locate the exact position of U7501 on the board with bitmap. (The normal value should be around 3.3V)Īccording to the circuit diagram, Voltage of PP3V3_S5_REG is outputted by U7501 DC-DC power converter. continue to locate L7560 of PP3V3_S5_REG on the bitmap, run voltage measurement of L7560, the measured value is 0.637V, which is abnormal. Then run voltage measurement of L7130, the measured value is 8.5V, which is normal. Check the DDR RAM and CPU frequency from the label, roll out the circuit diagram and bitmap. Next, detach the logic board and I/O Board from the enclosure, and connect the I/O Board to the logic board. Remove the SSD and WiFi module, confirm the board number of the logic board. then remove the lower case and disconnect the battery.
How to turn on macbook air 2015 serial number#
which indicates that the MacBook features not charging and not turning on issue.įirst, confirm the serial number on the lower case. Then plug in the power source and press power button, it current displays as 0.013A-0.016A. Press power button, the MacBook won’t turn on.
How to turn on macbook air 2015 how to#
Now, following to see how to troubleshoot MacBook won't power on issue. REWA never lets you down and always has an EFI chip solution for MacBook unlock repair for you. Actually, you can find the problem directly based on experience if you are an old hand. The fault is finally confirmed as to be caused by fuse damage due to short-circuited capacitor on the main power supply circuit. For our MacBook Air won't turn on repair case today, in order to demonstrate a complete repair process, we started from main power supply inductor in this video. For repair technicians, their repair work usually goes differently, since the problem can be fixed and solutions may be flexible.