Technical Support Apple 820-3115-B

[lazaro089]

I have an 820-3115-B (A1278). Fanspin, no video.
I'm on S0 state. I have PLT_RST_L =3.3V But no CPUIMVP_AXG_PGOOD.
Doing some readings, i checked for CPUIMVP_UGATE1G on the oscilloscope. The U7400 isn't trying to switch the MOSFET. Checked for CPUIMVP_VR_ON (U7400 enable signal) I'ts 3.3V.

CPUIMVP_PGOOD = 3.3V also.

So CPU it's getting power but Integrated Graphics isn't. Already tried another two U7400 from a donor board. Also changed Q7550

CPUIMVP_UGATE1G = 0V.

 

[Hosein Asadolahi]

I have an 820-3115-B (A1278). Fanspin, no video.
I'm on S0 state. I have PLT_RST_L =3.3V But no CPUIMVP_AXG_PGOOD.
Doing some readings, i checked for CPUIMVP_UGATE1G on the oscilloscope. The U7400 isn't trying to switch the MOSFET. Checked for CPUIMVP_VR_ON (U7400 enable signal) I'ts 3.3V.

CPUIMVP_PGOOD = 3.3V also.

So CPU it's getting power but Integrated Graphics isn't. Already tried another two U7400 from a donor board. Also changed Q7550

CPUIMVP_UGATE1G = 0V.

check PM_MEM_PWRGD and PM_MEM_PWRGD_R signal

 

[lazaro089]

Sorry for the late response. It goes UP to 3.3V Then 320ms after, it goes down.

 

[lazaro089]

Sorry, I gave you a wrong reading.
In my previous post I posted the reading for PM_MEM_PWRGD_L

PM_MEM_PWRGD is stable at 1.5V

 

[Tara Laptops]

In my 820-3115 , S5_PWRGD is getting generated but PM_RSMRST_L is missing. Tracing the signal i find PM_SLP_SUS_L is missing. What should i check in PCH. ?

 

[Notebook Centro CHILE]

In my 820-3115 , S5_PWRGD is getting generated but PM_RSMRST_L is missing. Tracing the signal i find PM_SLP_SUS_L is missing. What should i check in PCH. ?

Check the status of U7930, even if there is dirt, also R7933.
good luck

 

[Notebook Centro CHILE]

I have an 820-3115-B (A1278). Fanspin, no video.
I'm on S0 state. I have PLT_RST_L =3.3V But no CPUIMVP_AXG_PGOOD.
Doing some readings, i checked for CPUIMVP_UGATE1G on the oscilloscope. The U7400 isn't trying to switch the MOSFET. Checked for CPUIMVP_VR_ON (U7400 enable signal) I'ts 3.3V.

CPUIMVP_PGOOD = 3.3V also.

So CPU it's getting power but Integrated Graphics isn't. Already tried another two U7400 from a donor board. Also changed Q7550

CPUIMVP_UGATE1G = 0V.

Check the status of J9000, read signals in L9080, clean the LVDS connector, confirm that the video cable is in good condition.
Confirm if there is a screen without backlight, with dark image (light the apple with a flashlight)
good luck!

 

[Tara Laptops]

=PP3V3_SUS_PWRCTL . this input is missing. Tracing the signal i find PM_SLP_SUS_L is missing. before this PM_SLP_L , i want to know what should i chk in PCH ?

 

[Patrick Ribbsaeter]

=PP3V3_SUS_PWRCTL . this input is missing. Tracing the signal i find PM_SLP_SUS_L is missing. before this PM_SLP_L , i want to know what should i chk in PCH ?

Check PM_BAT_LOW

 

[Tara Laptops]

PM_BATLOW_L .This signal ?

 

[Patrick Ribbsaeter]

PM_BATLOW_L .This signal ?

try post more voltages and measurements you have done. and follow what everyone says here