missing PM_SLP_S5_L on a 820-4924a

Nick

New member
no liquid damage signs anywhere, not dropped. at first all rails were present, cpu becoming warm but no spin. after a bit it went worse. 5vs5 and 3.3sv5 present, but PM_SLP_S5_L so no 5vs4. no corrosion sign anywhere.
 

2informaticos

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Don't get any pulse at PM_SLP_S5/4_L?
PM_SLP_SUS_L present?
Are you using original Apple charger, 60/85W?
Check SMC_ADAPTER_EN, PM_BATLOW_L and S5_PWRGD...
 

Nick

New member
PM_SLP_S5 completely 0 no pulse
PM_SLP_S4 ditto

brand new original 85 watt. whole charger not just the cable

SMC_ADAPTER_EN = 3.39v
PM_BATLOW_L = 3.34v
S5_PWRGD= 3.32v
 

2informaticos

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"PM_SLP_SUS_L present?"

Check RTC signals and PCH_DSWVRMEN, PM_DSW_PWRGD, PM_RSMRST_L.
PM_PWRBTN_L reacts when you toggle SMC_ONOFF_L?
 

Nick

New member
SRTCRST# 3,3v
INTVRMEN# 3.11v
RSMRST# 3.31v
PWRBTN# 3.42v

PM_SLP_SUS_L 3.34v
PCH_DSWVRMEN 3.34v
PM_DSW_PWRGD 3.42v
PM_RSMRST_L 3.31v

PM_PWRBTN_L 3.42 on normal state 1.02v after shorting SMC_ONOFF_L but once it went to 0.34v
 

2informaticos

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32KHz oscillation comes out from U1900?

"PM_PWRBTN_L 3.42 on normal state 1.02v after shorting SMC_ONOFF_L but once it went to 0.34v"
PM_SLP_S5/4/3_L react at the same moment?
 

Nick

New member
PM_SLP_S4 and s5 goes up to 3.3 for an instant when you plug in magsafe or when you short SMC_ONOFF_L then back to 0.

no chanhe on s3 that remains on 0

on the rtc my scope measures the 25mhz but they are not always present. 25mhz present for a sec, then nothing then back and so, 32khz are present and well stable
 
Last edited:

2informaticos

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"PM_SLP_S4 and s5 goes up to 3.3 for an instant when you plug in magsafe or when you short SMC_ONOFF_L then back to 0."
So SMC so power button info to PCH and this one reacts too.
In this case, check if power supplies controlled by SLP_S5/4 pulse at least; should do it...

25MHz comes out only when board starts; or tries to do it.

Check again, better with o-scope, if SLP_S3 pulses at least.
 
Last edited:

Nick

New member
i just found out that
c2436
c2407
c2441
c2401
c2432

have been riped off from the board.. but i doubt they are the cause of my issue
 

Nick

New member
also yes 5vs4 and all the stuff commanded by SLP_S5/4 pulse at button press/magsafe insertion
 

Nick

New member
also slp_s3 pulses for a micro instant but i can detect it only with the oscilloscope
 

Nick

New member
i checked the bios chip.

spi_mlb_io0_mos1
spi_mlb_io1_mos0
spi_mlb_io2_wp_l
spi_mlb_io3_hold_l

are stuck at 50hz.
 

2informaticos

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Check if all power supplies controlled by SLP_S3 pulse too; the _S0 ones.
ALL_SYS_PWRGD should pulse too.
If not, one S0 supply is bad...
 

Nick

New member
pin 7 jumps to 2.66
pin 3 jumps to 3.47

only at magsafe connected or on button pressed
 

2informaticos

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That means even CPU VCORE tries to appear and PCH knows that.
Check now SPI termination resistors and traces around SPI chip U6100.
You can also try new BIOS.
 

Nick

New member
tried a new bios but nothing changed. u6100 seems healthy on my reader

r6130
r6131
r6122
r6123

seems ok

al bios pins but gnd have 3.3 v
 

2informaticos

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Staff member
3.3V at SPI chip means PCH doesn't access it.
There are 24 resistors, not 4...
Check U6101 too, resolder both chips.
Be sure no corrosion there, nor on U1950 area.
Do you get 24MHz oscillation at Y1915?
 

Nick

New member
no oscillation on y1915

will reflow u6101 but i see no oxyde

checked:

r6110 ok
r6111 ok
r6112 ok
r6113 ok
r6118 ok
r6119 ok


r6114 ok
r6115 ok
r6116 ok
r6117 ok

r6120 ok
r6121 ok
r6122 ok
r6123 ok
r6130 ok
r6131 ok

r6133 ok
r6132 ok
r6128 ok
r6127 ok
​​​​​​​r6126 ok
​​​​​​​r6125 ok
 
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