A2179 820-01958 slow, hot cpu core 4/5

[PapaRayRay]

Came in, no power, liquid damage. Ultrasonic cleaning allowed me to power on and boot very very slowly. Keyboard back light area looked a bit rusty but was functioning I removed funky looking caps just to clean up and re-solder, continued working but computers very slow, I imagine it’s a sensor issue and maybe I’m struggling to determine which sensor it is and where to check, I believe I have checked the areas that I can gather are sensor related but to no avail. I have backed up the data successfully, I am not able to boot to an external drive the screen just goes black, same thing for recovery or anything else other than holding down the option key or successfully booting very slowly to the internal drive normally. The computer visibly appears to be doing the proper stuff to go into the DFU mode but is not recognized an Apple configurator 2.

 

[2informaticos]

Some heatpipe temp seems to be high too; can't read it in that picture.

Can you start in diagnostic mode?
Fan spins normal speed?
Did you try known good trackpad board/flex?

 

[PapaRayRay]

Sorry, I chose the small file for the photo and I guess it blurred “heatpipe outgoing air 128° C” it doesn’t let me start in diagnostic mode, The fans seem to be spinning at a normal speed, I don’t have a good trackpad board on hand, this one “looks” to be fine I also had to ultrasonic clean that; I did however put a new flex. I also tried with the board disconnected.

 

[2informaticos]

Trackpad board is the first suspect here.
You can also try disconnecting the webcam; is on T-CON board.

BTW, any reason to quote an entire post, visible few centimeters above?

 

[PapaRayRay]

I ordered a new touchpad keyboard board I don’t think I have one, I’ll go through the rubbish at home to see if I’m overlooking anything; is there anyway that I can test if it is that without waiting for the new one, it arrives at the end of October and I didn’t have the option to make it faster freaking CHINA! Also about quoting the entire message I didn’t realize that I could just erase the quote I normally don’t hit reply I just do a new comment and while reading through other threads the other day I saw that you said it was smarter to hit reply.

 

[2informaticos]

"You can also try disconnecting the webcam; is on T-CON board."
Tried that?

 

[PapaRayRay]

So, I am very much still in the learning stage; I did some googling and I spoke to the friend I have that is a little more advanced than I am. I’m not exactly sure what the T-CON board is I feel like this is it from what I gather. I tried a cracked display to see if it would change anything except the two cracked displays I have are insanely cracked so it’s very hard to tell actually more like I see the Apple jumping around on the bottom for what appeared to be very very long, I’m not confident that this is a good test so I would like to do what you’re saying with disconnecting the webcam which I’m having trouble figuring out exactly what it would be I don’t think it’s any of the flexes right? Maybe? Unless I’m wrong so I used the cracked screen as a test to make sure that I could remove the shields without damaging the flexes, if I have to remove the flex I certainly will. But I would like to know that I’m properly doing what you suggest. I guess that’s a long way of saying, What is the T-CON board and which is the webcam?

 

[2informaticos]

OK, the small connector near the video connector; that is for webcam.

BTW, disconnecting MLB video cable and testing with external monitor, has the same effect; no webcam available.

 

[2informaticos]

If the fan increases speed in time, then you should try known good trackpad/flex.
An issue with ALS interface (placed on webcam), is now discarded.

 

[2informaticos]

At least 01521 board doesn't work properly without good battery connected.
Its fan spins to max in such, case; as the symptom described for you board.
So get known good battery to test.

But now, as you told us about corroded audio board, I think some T2 data lines have been affected.
Usually SPKRAMP_RESET_L gets shorted (inside T2), being next to PPBUS_G3H on the audio connector.

 

[PapaRayRay]

I try to do as much as I can with the direction you point me in to make the best use of your knowledge and learn as much as I can; I wish I knew more to make it easier for you to help me but I will definitely get there, I’ve learned so much since May this year. Thank you. I can’t wait to spend less of my time figuring stuff out.

•Battery eta 1/2 days from today.
•SPKRAMP_RESET_L: Definitely shorted, I removed R6402, C6104 just to be sure neither would be the cause and those are fine but short continues (I put them back.)
To be clear, when you say, “inside T2,” do I remove and re-ball T2? Or do I check else where? I clicked around and checked stuff I thought looks related and I think it was all fine everywhere else…

 

[2informaticos]

An internal short can't be eliminated with reball; T2 is dead, RIP...

 

[PapaRayRay]

And is testing on the two components and the corresponding test pad, like, I put the multimeter in continuity mode and checked if it beeps to ground with the board disconnected from power, is this the proper way to check if that is shorted? It beeps on all of that.

 

[2informaticos]

Yes, that short points to bad T2...

 

[2informaticos]

Read the forum posts daily and take notes when find relevant information.
Last night posted in a thread about T2...

 

[PapaRayRay]

Ty