820-3476-A " I have 5 boards all with the exact same problem " PM_SLP_S4_L HELL

[KC Micro Tronix]

820-3476-A " I have 5 boards all with the exact same problem " PM_SLP_S4_L HELL

I was digging through the scrap pile today and I noticed I had 5 820-3476-A boards all with what looks like PCH problems. All power up 3V rail but the 5V is missing. And ofcourse the PM_SLP_S4_L is not present.

PP3V3_SUS is as it should be.
PPVRTC_G3H is good.

I do not have a working board as a reference.

Do these boards all just die like this? What am I missing?
Statistically what is the common fail when they do this? This has to be a signature issue because I have so many.

 

[2informaticos]

"PPVRTC_G3H is good."
Did you also check all 4 RTC signals derived from it?

Trigger SMC_ONOFF_L signal and look for any reaction (drop pulse) at PM_PWRBTN_L.

 

[KC Micro Tronix]

I appreciate your help. I am in new territory here.

PCH_INTVRMEN is 2.3v
PCH_INTRUDER_L 2.3v

I believe this is wrong and may be the source of my problem.
I checked resistance on those lines and it is quite high. No short.

RTC_RESET_L 3.3V
PCH_SRTCRST_L 3.3V

There is activity on PM_PWRBTN_L
about 1/2 a second after power on it pulses up.



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UPDATE. I AM A IDIOT!

I use a bench top power supply. Old HP unit similar to what Louis uses. I made my power cable long long ago off a brick I was given. I was not sure of i'ts wattage. I decided to cut and make a new one with a 83w brick just in case I screwed up here. Presto.. boards are alive!!!!!!

HOLY COW! I was going down a rabbit hole!

 

[2informaticos]

You will probably fry one board after connecting Magsafe a bit angled.
Will then unerstand why need to work with original charger!

 

[KC Micro Tronix]

I went thru the stack. Most are working. I don't use the original bricks. I need to see the current they are drawing so I get a understanding of what the boards are doing. I cut off the cords and use a HP power supply. Using "original bricks" will tell me nothing. I do however need to use the correct wattage cord as the programming is in the head not the brick.

I spent the afternoon digging through my pro boards and it looks like I have about a dozen or so that do power on and enter a S0 state. I am off and running on these boards. I am rounding up test screens now. Time to move to Pro boards.

I can't believe I was such a idiot on these.

 

[2informaticos]

If you get in S0 state, try known good BIOS file; just for test.
Do NOT clean me of original; as could be main BIOS corrupted area.