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Alienware 17 R3 LA-C912P missing voltages

B

Biggtechman

Member
Voltage tests done after power button press.

Pin 67 - 3.3V
Pin 124 - 3.32V
Pin 125 - 3.3V
Pin 37 - 3.3V
Pin 100 - 0.6mV
Pin 106 - 6.0mV
Pin 107 - 0.6mV
Pin 110 - 3.2V
Pin 115 - 3.3V

+3V_PCH_DSW - 3.3V
AC_PRESENT - 3.3V

No change at PBTN_OUT# pin 106 when ON/OFFBTN# in triggered

PM_SLP_SUS# - 8.26Mohm to ground
 
2informaticos

2informaticos

Administrator
Staff member
Looks like KBC problem, but PCH can also impede it to work correctly.
KBC should send out PCH_PWR_EN, to generate +3VALW_PCH; check diode mode there.
Be sure to have good solders at KBC.
Check for broken traces, or moved components.
 
P

piernov

Moderator
Staff member
EC may be waiting for PM_SLP_SUS# to come up. Power sequence isn't clear on that. And of course it's handled by EC firmware so hard to know what it's doing.
 
P

piernov

Moderator
Staff member
Is +3VALW present before pressing power button? +1VALW is never present right?
What's the resistance to ground on +3VALW?
 
B

Biggtechman

Member
Yes, +3VALW is present before and after power button, 13 ohms to ground, measured from cap CM11.
+1VALW is never present, measured from JP2.
 
2informaticos

2informaticos

Administrator
Staff member
You didn't post such a low resistamce for +3VALW before.
Could be PCH, but still a chance to be other chip connected there.

You can try removing chips (leaving PCH at the end), one by one.
KBC should be good, as you was able to read/write it.
 
P

piernov

Moderator
Staff member
If PCH is warming up with only +3VALW present, and +3VALW is 13 ohms to ground, I'm pretty sure the PCH itself is partially shorted somehow, and it would also explain why PM_SLP_SUS# doesn't come up. In my opinion next step would be replacing the PCH (if you have a BGA rework station).
 
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