820-2879 Green Light, No Power

[Puevig reven]

I have a 820-2879 with no water damage, has a green light but does not power on. All S5 power rails are present, but all S3 and S0 rails are missing. PM_SLP_S4_L is missing too and I believe this is what is responsible for enabling the S3 rails? Does U1400 create PM_SLP_S4_L on this machine or is this the SMC?? I am extremely confused-any help would be great.

 

[dukefawks]

Resistance to GND on 3V42 rails and both RTC Xtal pins?

 

[Puevig reven]

I get .298 on PP3V42_G3H

 

[dukefawks]

Read my post and try again....

 

[Puevig reven]

And I am getting .829 on both RTC Xtal rails

 

[Puevig reven]

I measured resistance to ground on RTC_CLK32K_XTALOUT and RTC_CLK32K_XTALIN and receive .829.

 

[Puevig reven]

I apologize Duke- but I am confused

 

[dukefawks]

RESISTANCE not diode!
How are you turning this on? Are you shorting the power on pads on the board?

 

[Puevig reven]

I went ahead and measured resistance to ground on the following rails:
PP3v42G3H_SW .299
PP3v42G3H_FB .681
PP3V42G3H_BOOST .596

 

[Puevig reven]

Red probe on ground and black on component in diode mode does not give me the resistance to ground??

 

[Puevig reven]

Yes I am trying to turn it on by shorting the pads- and also I tried a keyboard too.

 

[Puevig reven]

I am still a novice at this stuff this is the resistance readings I am getting:
RTC_CLK32K_XTALOUT 21.50
RTC_CLK32K_XTALIN 14.69
PP3V42_G3H 22.48

 

[larossmann]

duke means he needs units.

22.48 miles per hour, kilometers per second, pounds, ohms, megaohms, degrees celsius etc.. ?

less than 30,000 ohms to ground on PP3V42_G3H usually means dead MCP(aka fucked). We can only determine this if we know what those numbers mean

the meter will usually have a little m or a k to denote million(or milli, depending) or thousand

 

[Puevig reven]

thank you!
RTC_CLK32K_XTALOUT 21.50k
RTC_CLK32K_XTALIN 14.69k
PP3V42_G3H 22.48k
all kilo ohms

 

[dukefawks]

Now measure from both of the Xtal pins to 3V42 bus.
Xtal pins to GND should be in the Mohms.

 

[Puevig reven]

RTC_CLK32K_XTALOUT is 14.6 Mohms
RTC_CLK32K_XTALIN is 21.6 Mohms

 

[dukefawks]

PPBUS, PP3V3_S5, SMC_LID?
Does PM_PWRBTN_L toggle when you short the power pads?
Does PP5V_S3(L7260) come high after shorting power pads?
Check all coils for short to GND?