Apple a1278 notebook water damage no booting repair

Machine model: Apple a1278

Mainboard version number: 820-3115

Fault phenomenon: notebook water damage no booting

Maintenance process:

water damage is located near isl6259, which is a Previously repaired board, and the two current detection resistors are not on.water damage machine generally cleans the water damage position carefully.

Apple a1278 notebook water damage no booting repair Figure 1.

It is found that the total ground plate is on the low side.Use multimeter to measure the common point to each Inductor.

Apple a1278 notebook water damage no booting repair Figure 2.

The sense and common point of VCC were 0.Remove the set display VCC MOSFET.The common point returned to normal.

Apple a1278 notebook water damage no booting repair Figure 3.

After replacing MOSFET, we tried it. As a result,MOSFET was burned again, and PMU and MOSFET were replaced together.Return to normal.The current jumps to 1.1a.

Apple a1278 notebook water damage no booting repair Figure 4.

The machine is displayed in 1.1a or so, and the wave pattern of EDID has been measured.820-3115 water damage, processing near 6259 chip, replaced CPU VCC and integrated display MOSFET, and the maintenance was successful.