Repair of MacBook a1932 water damage fan running wildly

Repair  of MacBook a1932 water damage fan running wildly

Machine model: MacBook a1932

Fault phenomenon: it can be started but the fan is running wildly

Maintenance process: at first, I thought it was a peripheral problem, but I replaced another set of casing, and the fault was still the same.After entering the system, I didn’t even recognize the battery. As soon as I pulled out the charger, I stood by.

MacBook a1932 water damage fan running wildly, battery maintenance Figure 1

Using Apple’s online diagnosis, we found two faults error code. The first one is that the battery cannot be identified, and the second is that the SMC may be faulty. However, Apple’s diagnosis can not explain any detailed problems.

MacBook a1932 water damage fan running wildly, battery maintenance Figure 2

It was found that there was something wrong with the battery BTB connector when the machine was disassembled.corrode phenomenon was found. This picture was taken later.

MacBook a1932 water damage fan running wildly, battery maintenance Figure 3

With an oscilloscope, the SCL pin of the battery is only 3.3V, but there is no waveform. This problem multimeter should be hard to find.

MacBook a1932 water damage fan running wildly, battery maintenance Figure 4

After checking, it was found that the wire from q6950 to r6951 to the battery BTB connector was disconnected, and a wire was lost to solve the problem.

water damage nce of MacBook a1932

MacBook a1932 water damage fan running wildly, battery maintenance Figure 6

MacBook a1932 water damage fan running wildly, battery maintenance Figure 7

Apple’s design is not very good. The T2 chip replaces the original SMC, so the battery power and temperature information is managed by T2, but the I2C of T2 is 1.8V, the battery is 3.3V, and the q6950 plays a role of signal amplification.