820-00164-A "No Audio"

[KC Micro Tronix]

The Intel audio device shows up in "about this mac" but no sound. I have changed the DC-IN no help. Performed a board swap and that fixed the problem so I know it is on this board.

The Audio just disappears on it's way to the DC-In board. Where the hell is it?

 

[2informaticos]

Did you locate the problem on the MLB, or LIO board?
Also be sure the LIO flex is good.
Inspect both connectors too.

 

[JohnB8812]

If you're getting audio devices in OSX, you have a bad I/O Board, I/O Cable, or bad speakers.

 

[KC Micro Tronix]

replacing the board does fix the problem. The DC-IN board was tried first. And did not help.
I have already fixed the MacBook with a board swap but have the board and would still like to figure it out.

 

[JohnB8812]

If a board issue, inspect J9500 for corroded pins/traces. All audio circuit is on the I/O Board besides the 1v5 switch. If that switch is bad, usually you get no audio devices found.

 

[KC Micro Tronix]

I am playing with the "no audio" board again. I am glad to know that the audio IC is on the I/O board.
This time the board is in a totally different MacBook. Same model but completely different machine.

I performed a detailed inspection of J9500. Looked perfect. I checked every pin on top and bottom. Pushed on each one on bottom checking for possible bad solder connections. It is absolutely perfect. No corrosion of any kind. Pins all looked good.
I am using the ribbon that was with this machine so it is a different one than last time. This tester machine worked perfect.

About this Mac
Built-in Speaker
Built-in Line Output
Intel High Definition Audio

NO SOUND!

1.5v PP1V5_S0SW_AUDIO
3.3v AUD_PWR_EN

(tests performed with no ribbon)

SPKRAMP_INR_N
SPKRAMP_INR_P

I take it these are the data lines to the on board Right speaker?

Are the HDA lines for the sound chip? I am a little lost here.
If it detects the audio card it must use different lines for sending data to it than seeing it.
Perhaps I have a hung data line. Not sure what to trouble shoot.

 

[2informaticos]

You cannot have sound, if LIO flex is disconnected.

I'm not sure if I understood you correctly?
Is the same board, or you got different board with no audio issue?

Start always trying known good LIO flex/board for this issue.
Also be sure LIO board is compatible with your MLB model.

 

[KC Micro Tronix]

I understand you cannot have sound if ribbon is not connected. I wanted to check sound power rails.

This is the same broken board. I just tested it in a different MacBook
Everything is known good and tested good. Fault follows the board.. This is a macbook I already fixed that uses the same board.

I was asking what data lines are for Sound board detection and what ones carry the data back and forth. I don't have a schematic for the DC-IN board. I guess I can look at one and pull a data sheet on the sound IC, Trace it back.

I should get a logic analyzer for strange stuff like this. Would be interesting to compare. Back in the day when working on arcade machines a Logic analyzer helped me fix so much stuff it was crazy. I couldn't live with out one.