820-00923 not turning on

arnonabuurs

New member
Hello, I have a touchbar 13 inch that came in dead. Inspected the board with microscope in details, nothing to see no liquid damage or bad IC, board looks as new. I have 1.06v on PPVCC_S0_CPU that drops to 0.76v after some time, and after a while boards turn off. Mouse has activity. Missing PPVCCIO_S0_CPU and PPVCCEDRAM_S0_CPU. Anything I can check or RIP?

Edit: all other voltages present upto 0.6v
 
Last edited:

2informaticos

Administrator
Staff member
Machine doesn't turn on, but USB mouse has activity???
You meant turns on (as you get more voltages, not only S5), but doesn't work properly.
Should be good if you check USB activity with USB OSX pendrive; flashing Link LED is the best confirmation.

Other people reported to me such kind of lost balls, also on the bery clean boards, without signs of previous repair attempted.

Compare diode mode to ground on L7960 with another board.
PPVCCIO_S0_CPU is controlled by U7800 (PMIC).
Do you get PVCCIO_EN?
 

arnonabuurs

New member
The mouse LED turned on, but actually not flashing. L7960 seems shorted, 0.059v. I only have a donorboard without CPU that reads 0.469v nothing else to compare with at hand :(. I have 3.3v on PVCCIO_EN
 

2informaticos

Administrator
Staff member
That reading w/o CPU is useless.
060 doesn't seem to be short, as that is common power rail for PCH and CPU.
Check R7961-64 and C7963.
You can also change U7960.
If still the same, possibly bad U7800; reflow it at least.
 
Top