{"id":2219,"date":"2021-03-09T10:33:12","date_gmt":"2021-03-09T10:33:12","guid":{"rendered":"http:\/\/192.168.2.19:8666\/?p=1"},"modified":"2024-09-24T11:16:48","modified_gmt":"2024-09-24T03:16:48","slug":"how-to-fix-a-macbook-pro-that-wont-turn-on","status":"publish","type":"post","link":"https:\/\/rewa.tech\/de\/how-to-fix-a-macbook-pro-that-wont-turn-on\/","title":{"rendered":"Wie man ein MacBook Pro repariert, das sich nicht einschalten l\u00e4sst"},"content":{"rendered":"

Today we will share a case about repairing a MacBook Pro 13″2018 (A1989) that won\u2019t turn on.<\/p>\n

Dr\u00fccken Sie die Einschalttaste.<\/p>\n

The MacBook won\u2019t turn on.<\/p>\n

Schlie\u00dfen Sie den BY-3200<\/a> power cable and the input voltage is 20V.<\/p>\n

The current reading on the DC Power Supply stays at 0.047A.<\/p>\n

\"DC-Stromversorgung\"<\/p>\n

Unplug the power cable.<\/p>\n

Next, we need to disassemble the MacBook and test.<\/p>\n

The MacBook model is A1989. Remove the screws and disconnect the battery connector flex cable.<\/p>\n

\"How<\/p>\n

Plug in the BY-3200 and the input voltage is 5V.<\/p>\n

The current reading on the DC Power Supply stays at 0.059A.<\/p>\n

The power supply of the motherboard is only 5V, which is abnormal.<\/p>\n

\"How<\/p>\n

The normal power supply should be 20V.<\/p>\n

It indicates that the motherboard has malfunctioned.<\/p>\n

Then we remove the motherboard and install the power connector flex cable.<\/p>\n

\"How<\/p>\n

The motherboard number is 820-00850-07.<\/p>\n

Open the schematic diagram and bitmap.<\/p>\n

U3900 is the T2 chip. U7800 is the power chip.
\n\"schematic<\/p>\n

Measure the standby voltage of the T2 chip, which is supplied by the U7800.<\/p>\n

Find U7800 on the schematic diagram. This table shows the standby voltage of T2 chip.<\/p>\n

\"standby<\/p>\n

Plug in the power cable.<\/p>\n

The motherboard current stops at 0.06A and the input voltage is only 5V.
\n\"MacBook<\/p>\n

Measure the power supply of the motherboard.<\/p>\n

\"How<\/p>\n

The measured voltage values are normal.<\/p>\n

It can be judged that the power supply circuit of the motherboard is good.<\/p>\n

Next, we need to decide if the fault (voltage failing to increase) is caused by T2 chip data problems.<\/p>\n

Find T2 chip on the bitmap and the location name is U3900.<\/p>\n

Search U3900 on the diagram and find the ROM chip for T2.<\/p>\n

\"How<\/p>\n

Copy signal SPI_SOCROM_MISO. Find SoC ROM and the location name is U4770. Find U4770 on bitmap.
\n\"How
\n\"How<\/p>\n

Find SoC ROM (U4770) on the motherboard. Remove SoC ROM chip with Hot Air Gun at 430\u2103.
\n\"Hei\u00dfluftpistole\"<\/p>\n

Get the BY-T200<\/a> and write the new SoC ROM data.<\/p>\n

Attach the chip to the seat of BY-T200. Pin 1 of the chip must align with the red dot on the tool.<\/p>\n

Then connect BY-T200 with the computer.<\/p>\n

\"MacBook<\/p>\n

Install the driver and open AsProgrammer.<\/p>\n

\"How<\/p>\n

Click Read ID and select MX25U3235F_1.8V.<\/p>\n

\"How<\/p>\n

Click Open file and select A1989 T2 ROM original data.bin.<\/p>\n

\"How<\/p>\n

Click Auto Program and click Yes.<\/p>\n

\"How<\/p>\n

Data writing has completed.<\/p>\n

\"data<\/p>\n

Unplug BY-T200. Remove the chip. Solder the chip back to the motherboard.
\n\"How<\/p>\n

Plug in the power cable. The BY-3200 shows an increase in input voltage from 5V to 20V.<\/p>\n

The current jump on the DC power supply is normal, which indicates that the motherboard is turned on.<\/p>\n

\"How<\/p>\n

Disconnect the power cable and install the motherboard.<\/p>\n

Plug in the power cable.<\/p>\n

The MacBook is turned on and can enter the system.
\n\"How<\/p>\n

Lastly, assemeble the MacBook.<\/p>\n

Connect the battery flex cable and put the back cover on.<\/p>\n

Plug in the power cable and press the power button.<\/p>\n

The MacBook is turned on and can enter the system. The fault has been cleared.<\/p>\n

\"How<\/p>\n

Zusammenfassung<\/strong><\/p>\n

In the first place, we used MacBook BY-3200 power cable to observe the change of boot voltage and current.<\/p>\n

The voltage values related to the boot circuit on the motherboard were found to be normal after measuring.<\/p>\n

To determine whether the fault was caused by data problems, BY-T200 Data Assistant was used to read and write the data of T2 chip ROM.<\/p>\n

After rewriting the ROM data of T2 chip, the MacBook could turn on and enter the system.<\/p>\n

The no power fault has been cleared.<\/p>\n

For more MacBook repair content, please visit our MacBook Repair Guide channel.<\/p>\n

Watch the video below to see how we fix a MacBook Pro that won’t turn on by restoring T2 chip data.<\/p>\n