A2141 fan can be turned on or off without display (resistance corrosion near GPU power chip)

A2141 fan can be turned on or off without display (resistance corrosion near GPU power chip)

applenotebookA2141, the fault is that the fan can be turned on or off and not displayed. When the motherboard was removed and powered on, it was found that the current was set at more than 200 mA, and the fan was always turning. The voltage of each inductor of the motherboard was measured, and it was found that the GPU power supply did not come out. How to repair it next, and then read the following!

[Fault model] A2141

[Fault phenomenon] is not displayed.

[Maintenance process] I received a machine sent by a customer for repair, the model is A2141, and the fault is that the fan can be turned on or off without displaying.

When the motherboard was removed and powered on, it was found that the current was set at more than 200 mA, and the fan was always rotating. After measuring the major inductor voltages of the motherboard, it was found that the power supply of the GPU did not come out. When the power supply was disconnected, and the opening conditions of the power supply chip of the graphics card were checked, it was found that a resistor was corroded.

A2141 Fan can be turned on or off without showing Figure 1.

According to the opening principle, the resistance bit number RA601, with the size of 1Ω, comes from the 5V power supply of the GPU power chip.

A2141 Fan can be turned on or off without showing Figure 2.

Without one power supply, the GPU can’t work normally. Pick a resistor of the same size from the material board and install it. The power-on test current can normally rise to more than a year, and the power-on test with button screen can be successfully lit.

[Maintenance result] The mainboard was installed, and the startup test was successfully lit. The recording, camera, sound and WiFi of the system test were normal, and the stress test of the baking machine was normal for half an hour. The maintenance was over.