MacBook Pro a1990 notebook cannot be turned on due to water ingress

Machine model: apple MacBook Pro A1990

Main board version number: 820-01041-A

Malfunction: Notebook water damage Won’t Turn On

Maintenance process:

I received an Apple MacBook Pro A1990 laptop. The fault is that it can be turned on occasionally. Most of the time,Won’t Turn On.

MacBook Pro a1990 notebook cannot be turned on due to water ingress figure 1.

Disassemble the machine and test it without PP3V3_G3H_RTC_X VCC.

MacBook Pro a1990 notebook cannot be turned on due to water ingress figure 2.

At the same time, the input terminal VCC PPBUS_HS_3V3G3HRTC_X is not available, and the ground diode value is only 13 ohms lower, which may have Short circuit on PPBUS_G3H Related circuit. Remove the Fuse of F7000 and F7001, and confirm that it is Short circuit of the load terminal. From the point of view, it is the same circuit as water damage corrode, and there is Short circuit corrode near the circuit of Capacitor VCC 20501.

MacBook Pro a1990 notebook cannot be turned on due to water ingress figure 3.

MacBook Pro a1990 notebook cannot be turned on due to water ingress Figure 4.

After removal, measuring PPBUS_HS_3V3G3HRTC_X is also generated.

MacBook Pro a1990 notebook cannot be turned on due to water ingress Figure 5.

But the main power supply 5V still can’t be boosted to 20V.

MacBook Pro a1990 notebook cannot be turned on due to water ingress Figure 6.

Have removed the CD3205 chip near corrode circuit.

MacBook Pro a1990 notebook cannot be turned on due to water ingress figure 7.

There is a slight corrode under pin. Clean up the Capacitor resistor with corrode around it, re-attach the CD3205 chip, and boost the voltage by 20V normally.