MacBook Pro A1708 No sound/audio, sound card is not showing up in the system repair

From Repair Wiki
MacBook Pro A1708 No sound/audio, sound card is not showing up in the system repair
Device MacBook Pro A1708
Affects part(s) Motherboard
Needs equipment multimeter, soldering iron, soldering station
Difficulty ◉◉◉◌ Hard
Type Soldering


This article is a stub. You can help Repair Wiki grow by expanding it

Problem description

When A1708 is not playing audio and the audio device is not showing up in the system

Example image (Figure 1) -- No image yet. Help expand this page by uploading it!

Symptoms

  • No audio out
  • Sound card not showing up in the system

Solution

It could be a chipped off R2041 on the backside of the CPU, so no AUD_PWR_EN on L6361 and therefore only 0.3 V on L83_1V8 for the U6300 chip. Installed new resistor and sound card shows up.

You may want to check these four main ICs responsible for sound on the 820-00840/00875 boards U6200/6300/6400/6420. Compare diode mode reading with known good board in regard to these ICs. Also refer to schematic and check VIN, enables, data lines (U6400/6420 AUD_I2C_SDA/ AUD_I2C_SCL) etc. Check values of all resistors associated with these four ICs (refer to schematic for values)