820-3462 No S0 PM_SLP_S3_L is Low ( shorted?????)

[Bouba148]

Small Water damage

PPBUS_G3H: 12.57V
PP3V42_G3H: 3.405V
PPVRTC_G3H: 3.343V

PP5V_S5: 5.053V
PP5V_SUS: 5.053V
PP3V3_S5: 3.343V

PP5V_S4: 5.054V
PP3V3_S4: 3.343V

PP5V_S3: 5.054V
PP3V3_S3: 3.346V

PP3V3_SUS: 3.342V

PP1V5R1V35_S3: 1.354V

No S0 State
No SMC Bypass mode

PM_SLP_S3_L: 2.327V
diode mode with red probe to gnd:
PM_SLP_S3_L: 0.088V shorted ????

Any suggestion before I'll pass it i the UC?

 

[Bouba148]

After UC Cleaning Still the same situation:

PM_SLP_S3_L: 2.318V
diode mode with red probe to gnd:
PM_SLP_S3_L: 0.088V

 

[2informaticos]

088 is to low for that signal.
Check first R1924 for corrosion.
Test disconnecting RIO flex and also clean J4410.
Remove R7978 and test again; also remove U2800.
Finally remains PCH and SMC; put good flux and reflow them, if needed.

 

[Bouba148]

BIG Sorry
PP3V3_S5 is 0V I was mesuring PP3V3_S5_AVREF_SMC because of OPENBOARD View pointing me at it......

which means NO S5 State at all

 

[Bouba148]

I've reflowed the SMC and now Ihave the S5 state back
also with U9410 removed , PM_SLP_S3_L is 3.331V

 

[Bouba148]

replaced also R7978 because I've lost it.
Machine fixed: Fans spins
So the issue was U9410 "shorting" PM_SLP_S3_R_L rail to gnd.
Don't think I'll put a new U9400, I will leave it without it which means no thunderbolt port A

 

[Bouba148]

I'm back with that board:
After I've put it back in the mbp, I had no bcklight ( fixed) and once ON it doesn't power OFF.
Tried to short the debug power pads ( R5015 R5016 ) still the same also with the keyboard connected I've pressed the power buton and mesured WS_KBD_ONOFF_L: this one passes from 3.397V to 0V which means the keyboard is OK.
I'm suspecting the SMC as if you read higher in the post I had to reflow it to recover the S5 state.
Any suggestion before I attempt a risky reflow again.

 

[2informaticos]

Always reball SMC if it reacts to reflow...

 

[Bouba148]

Ola 2Informaticos,
I've reballed the SMC, and it's still the same situation like before:
Marchine turning ON, fans slowly runs to max speed, and no way to turn it OFF by shorting the power pads or from the keyboard.

So I've attempted a reflow again and the machine is acting the same except now I'm mesuring 0.367V VS 3.372V at the power pads (SMC_ONOFF_L) .

I think the SMC is bad........What do you think?
Is there's something else I can check?

 

[Bouba148]

I did a Last reflow at 500°C and 120L/m and apparently it's working properly now : recovered 3,3v at smc_onoff_l and turning off when shorting power pads.
I left it on my desktop and will re assemble it later.

 

[2informaticos]

Probably SMC wasn't properly soldered on the board after reball...
Be sure to always use leaded solder.

 

[Bouba148]

re assemble everything and still the same problem, except that its reseting the SMC when shorting ( just a short contact not 5 sec ) the debupg power pads and not turning off.
When I press on the power botton of the keyboard it goes from 3.3V to 0.5V not less.

 

[2informaticos]

Start disconnecting perypherics from the logic board.
See when/if board starts to work correct again...