820-00239 Stuck at 5v - PP3v3_G3H at 1.4v

ytesfay80

Member
I have this board that doesn't look to have any liquid damage and is stuck at 5v and 0.21amps on all 4 ports. There isn't any boot loop just a steady 5v. I was getting 1.4v on PP3v3_G3H and so far I have replaced U6903, R6910-13, C6910/11/13/15/16 and D6902 .

I still get the same voltage but I noticed when I remove R6915 from the board I get 3.39v on PP3v3_G3H but I still get 5v on the charger but 0amps this time. When I put R6915 back on it goes to the original issue.

I visually inspected all the CD3215 chips and there doesn't look to be any damage to any of them or around them.
 

ytesfay80

Member
In diode mode to ground here are all the 3v3 LDO measurements.
CB308 - 0.487v
CB408 - 0.486v
C3108 - 0.484v
C3208 - 0.487v
1v8 LDO
CB305 - .048v
CB306 - .051v
C3205 - 0.478v
C3206 - 0.514v
C3105 - 0.475v
C3106 - 0.51v
CB405 - 0.481
CB406 - 0.515
1v1 LDO
CB304 - .498v
CB404 - .504v
C3104 - .498v
C3204 - .503v
 
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2informaticos

Administrator
Staff member
The values look good.
You should have a problem with other chip connected to 3V3_G3H.
Post diode mode to ground at C6920.
Injecting 3.5V there may help to find something with a good IR camera.
 

ytesfay80

Member
Okay I injected voltage and found that CB300 was getting really hot. I replaced that and now it turns on the trackpad clicks, I hear the apple sound that happens when you plug your charger in and the caps lock button turns green when pressed. The only thing is nothing appears on the screen.

Where do you first check for screen issues?
 

ytesfay80

Member
I get a light on my usb stick I plug in but there is no image or anything from an external tv plugged in.
 

2informaticos

Administrator
Staff member
Need to see flashing Link LED for boot pendrive.
Only then you have USB activity confirmed.

Caps Lock key reacts every time?
 
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2informaticos

Administrator
Staff member
In this case, the board is active.

Looks like integrated Intel graphics is bad.
Compare diode mode readings on EDP_INT_x lines with good board.
 

ytesfay80

Member
I don't have another board to measure against but I plugged in another display assembly I know worked in the past and that didn't work. This time i also saw ESC light appear on the touchbar
 

2informaticos

Administrator
Staff member
You can compare diode mode readings between data lines of similar pair.
One data pair should have same value on its data lines.
 
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