Touchbar 820-00923-05 Dead not turning on missing PM_SLP_S5_L

[Magneh]

Hello there!

I have a dead touchbar , no signs of life, which as far as I could get is missing PM_SLP_S5_L.
No signs of liquid damage, board seems pretty neat.

All the power rails read OK for this stage, and I'm using a 820-00239 schematic and BV.

This comes out from U0500 and I've measured some inputs :

PM_SYSRST_L 3.35V

PM_RSMRST_L 3.35V

PCIE_WAKE_L 3.35V

SMC_WAKE_SCI_L 3.31V


PM_SLP_S5_L is not shorted, 0.5v diode mode.

What else is needed to get PM_SLP_S5_L , any ideas?

Any missing measurements or photos, let me know

Thanks!

 

[2informaticos]

PM_SLP_SUS_L should go high first.
Post F7000 and L7660 voltage.

 

[Magneh]

Hi,

Yes, PM_SLP_SUS_L is 3.35V.

F7000 is 13.05V
L7660 3.35V

 

[2informaticos]

PM_PWRBTN_L reacts if you trigger SMC_ONOFF_L?
Use R5225/6 for this test...

 

[Magneh]

PM_PWRBTN_L is 1.24V and doesnt change even after shorting SMC_ONOFF_L

 

[2informaticos]

"PM_PWRBTN_L is 1.24V"
This is bad value.
Check for corrosion at J1800 area.
Be sure R1450 is OK

 

[Magneh]

J1800 area is clean, the board is as new

R1450 is OK.

I guess only thing pulling down this signal is the SMC or U0500 right?

Diode mode at PM_PWRBTN_L 0.52

 

[2informaticos]

Yeah, one of them.
Use quality flux and reflow first SMC.
Heat to 180-200 degrees, no more.
Maybe you have luck and is only crap under SMC, or PCH area...

 

[Magneh]

Yes!

This was a funny one.

After taking some time to inspect carefully the SMC area, I noticed a blurry stain under it on the 4th solder ball zone, the PM_PWRBTN_L contact point!

It was hard to check under it as the angle is not the best, but there it was.

Some flux, a good reflow . and the diode mode in that line rised up to 0.78 if I remember well.
So good hope.

Power up the board, and CPU vcore was there.
Assembled it and image present.

Will test the machine today, but definitely fixed!

Thanks 2informaticos !