820-00923 hot cpu, fan spin, no signs other signs of life

Dusten04

Member
Device History:
Ship in repair, client stated this on his notes:
The unit was working fine, it came in for a broken screen. After we replaced the broken screen, we lost functionality of the touch bar. Our next step was to replace the entire top case, with a new touch bar included. After we did this, the computer no longer turned on at all.

What I have done:
The first thing I did was plug in the unit, it was pulling 20v and about 30mA. I disconnected all the flexes, and plugged the board in, and it started pulling 20v - 400mA. Noticed a damaged touch bar connector (on flex, not on board) (if I connect battery, it will draw 20v-2.5amps)
I do have trackpad feedback,
no caps lock light.
No image (internal or external)
Also No USB activity
CPU does get hot(normal operating temp), fans do turn on when the CPU is hot enough.

What measurements I've taken:
VCC_S0_CPU: 1.06 then drops to about .640v after a few seconds.
PLT_RESET_L: steady 3v3

I am not sure exactly where to go from here. Never faced an issue like this.
 

2informaticos

Administrator
Staff member
VCORE looks like board boots.
Check for knocked of components first.

Really bad, if Touchbar connector was burnt.
U3900 is directly connected there; could be damaged now.
 

Dusten04

Member
Nothing knocked at all, he said battery was connected when he was disconnecting flexes to replace top case. He heard it chime, and thats when he realized he didnt disconnect the battery
 

2informaticos

Administrator
Staff member
Burnt connector generated an overvoltage, or temporary short to ground on some data line.
Working on the board without disconnecting battery, could also damaged something.
 
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