820-2915 missing PM_SLP_S4_L

Chuck60

Member
Hi I have a board missing PM_SLP_S4_L
Cpu prerequisites:
ppvrtc_reset_L=3.3v
Pch_srtcrst_L=3.32v
Pch_intvrmen_L=3.24v
Pch_dswvrmen_L=.489mv
Sysclk_clk32k_rtcx1=.489mv
PP3v3_s5=3.3v
Pp3v3_sus=2.7v
Pm_batlow_L=3.3v
Pm_rsmrst_L= 3.4mv
Pm_pwrbtn_L=3.45v

I also have power u6100 on pins 8,5 but not on pin 1 (SPI_MLB_CS_L)=.489v

Shouldn’t the bios output 3.3 on pin 1 ? Is it a bios or Should I try that trick of hearing cpu like on the last board?
 

Chuck60

Member
I’m sorry I was Hurricane preparing. no it’s was a bad solder joint. It’s good now r1915 pin2=3.2v checked it multiple times. Touched up the joint. Now on to why my Pp3v3_sus is low
I’m going to check the Level of Q7802/20 voltages.
As you suggested
 
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Chuck60

Member
At Q7802
Pins:
1-GND
2-P3V3_S4_EN= 479mv
3-P3V3SUS_EN_L= 3.3v
4-GND
5-PM_SUS_EN=0
6-PP3V3S4_EN_L=0

Q7820
Pins:
1- PP3V3_SUS=3.3v
2-P3V3SUS_SS=3.3v
3-PP3V3_S5=3.3v
4-PP3v3_S5=3.3v
 

2informaticos

Administrator
Staff member
"it did drop down to 400mv and went back up to 1.6v"
Then what this mean?

Check if all PM_SLP_Sx_L signals pulse at same time when PM_PWRBTN_L drops.
 

Chuck60

Member
Ok my mistake. When you ask me to short SMC_ONOFF_L to ground and check to see if I had a drop in voltage at PM_PWRBTN_L yes it does drop down to 400mv and then back up to 1.6v and when I said "it did drop down to 400mv and went back up to 1.6v" I was referring to PM_PWRBTN_L
I will check to see if all the sleep signals “PM_SLP_Sx_L” pulse at the same time as
“ PM_PWRBTN_L” thank you for your help
 
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2informaticos

Administrator
Staff member
PM_PWRBTN_L also MUST go back to 3V when you realease power button.
In fact, it should be steady 3V and only drops when SMC_ONOFF_L is triggered.
 

Chuck60

Member
Ok on R1985 on pin 1 =3.3v on pin 2=1.6v
I removed R1985 and measured it is 1k what schematic say is correct. When I power the board with out resistor I get pin 1= 3.3v and pin 2 = 1.6v so the 1.6 is either coming from smc or pch. I get 1.6v from Both pins of r2502 With R1985, R2585 removed. But on the schematic it say “in” to smc :( so is this signal being sent by pch low ? Or should I remove R2502?

I will post the “PM_SLP_Sx_L“ signals as soon as I figure out why PM_PWRBTN_L is low as of now the sleep signals are 0v but I’m guessing that has a lot todo with the resistors I have removed.
 
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2informaticos

Administrator
Staff member
Either PCH, or SMC pull down PM_PWRBTN_L.
You can try heating PCH with quality flux, to discard an issue created by accumulated crap underneath.
Also do the same with SMC...
 
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