Apple MacBook Air a1465 laptop no booting repair

Machine model: 15 model MacBook Air a1465

Mainboard version number: 820-00164-a

Fault phenomenon: notebook no booting, no CPU VCC, CPU MOSFET chip 1 pin, no EN.

Front of main board

Back of main board

Maintenance process:
The motherboard is connected with DC power supply, and there is a standby current of 0.047 when it is plugged in. The first feeling is that the current is a little low.

Apple MacBook Air a1465 notebook no booting repair Figure 1.

Continue to measure each big Inductor VCC, and find that only CPU VCC does not come out. Immediately measure the first pin chip of CPU MOSFET and find that there is no EN.

Apple MacBook Air a1465 notebook no booting repair Figure 2.

This should be a common failing. The maintenance has studied this fault before, and the train of thought is still very clear. This EN CPU_VR_EN is sent by the CPU, when the CPU receives the CPU_VCCST_Pwrgd directly after conversion issued, while the CPU_VCCST_Pwrgd was developed by all_SYS_Rgpm and PWD_SLP_S3_L was transformed by u1930.

Apple MacBook Air a1465 notebook no booting repair Figure 3.

Measure all_SYS_PG is only 0.10v.

Apple MacBook Air a1465 notebook no booting repair Figure 4.

It seems that the problem was caused by q8150. It was disassembled from Parts motherboard and replaced. The result was the same.So we measured the VCC of each pin in q8150.

Apple MacBook Air a1465 notebook no booting repair Figure 5.

Calm down to a good analysis, the first thing to know is that q8150 the 4th pin must be 3.3V, which means that the internal Q1 of q8150 can not be conducted, that is, grade g must be low potential, then the internal threetriodeAll of them must be on state. In this way, the problem is clear.Since the three internal triodes must be connected, the VCC of class B should be 0.7V, that is to say, the 1 pin, 5 pin and 7 pin of q8150 must be 0.7V, which is the same as that of my previous good board test, and the VCC measured by me is shown in the figure below.

Apple MacBook Air a1465 notebook no booting repair Figure 6.

Obviously, the 7th pin cannot meet the requirements, and the 7th pin is made by pp3v3_S0 is divided by resistance r8158 and r8159, and pp3v3 is measured_S0 VCC has only 0.77v.

Apple MacBook Air a1465 notebook no booting repair Figure 7.

It seems that the problem lies in pp3v3_S0 VCC is on. Is this VCC disconnected?So pp3v3 was measured_The origin of ppv30_S0_FET_R is also 0.77v.

Apple MacBook Air a1465 notebook no booting repair figure 8.

The measured diode value to ground is 388 ohm, normal.PP3V3_S0_FET_R is a standby VCC pp3v3_S5 was transformed from u8030.

Apple MacBook Air a1465 notebook no booting repair Figure 9.

The working condition of the u8030 is simple.VCC and opening are normal.VCC is standby VCC, which is normal. Next,EN is normal.Now that VCC is turned on, there is no Short circuit. Only the chip itself is damaged. Remove the chip and replace it.

Apple MacBook Air a1465 notebook no booting repair Figure 10.