A1708 820-00239 no display

[TBFix]

I have a unit here that J4402 was getting very warm with no display. 20v is getting to the board. it draws 700ma and cpu gets warm but no chime. J4402 had a bit of damage so will replace it. board acts the same with touchbar connected or not. the diode reading on j4402 are all good.

 

[2informaticos]

Missing touchbar backlight/image, or internal LCD image problem?
Tested external video and USB activity?

 

[TBFix]

Hi the main display and the touchbar display are not working. No external video or usb activity.

 

[2informaticos]

So the machine dosn't boot; you can't complain about any kind of display in such case.
What is CPU core voltage after 10-15s?

 

[TBFix]

L7220/L7210 are 1.06v
L72701.05v

L7410/L7420/L7430 all 0v

Im told it powered up and display and touchbar worked then the connector of touchbar got very very warm and after that no display on screen and no touchbar display.

 

[2informaticos]

VCORE should drop from 1.06V to 0.6V aprox.
In your case, the board doesn't really boot; just stays on.

Which J4402 pins have been damaged?

 

[TBFix]

Looks like the ribbon cable may have inserted in the wrong pins.

 

[2informaticos]

Check if you get correct voltages on that connector pins.