A3113 corrosion to LAS = No keyboard, yet screen and trackpad work fine

[ronaldopdias]

Hi All.

I have a A3113 MacBook Air 13" (M3) that had minor liquid damage. The screen remains on if the lid is closed, the keyboard doesn't work, but trackpad and Touch ID does.
The LAS was corroded, but I have tested it on an A2681 (M2) and it functions fine. Anyway, I ordered a new one and replaced it and calibrated it with Apple.

I have checked the main voltages going to the daughterboard and they are present. Diode mode reading on the LAS line which goes direct to the SoC is also correct, no short.

So then I replaced the daughterboard, and still no change in symptoms.

[ronaldopdias]

Update - The M3 A3113 has two mechanisms to determine lid position, the lid angle sensor AND a hall effect sensor.
There is a hall effect sensor built into the keyboard backlight cable. In my case it was sending voltage to UR300 correctly depending on whether i was putting a magnet there or not, but I was getting no change in output on pin 8, which stayed at 1.7V.

I replaced UR300 with one from an M2 Air, now the Mac correctly detects whether the lid is open or closed. However, still no keyboard at all....