Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

[platinumsteel]

Hi guys I have a Macbook Pro Late 2012 820-3462 13 inch that i bought of ebay that was not powering on.No signs of liquid damage under microscope.Board looked like no one tampered with it before. I diagnosed and there was a short on PPVIN_S5 and i injected 0.8v and there was a 100 milliamp short on a capacitor C7523 which i had to use my lips to pinpoint.Removed it and board powered on and worked fine.I had it using every day for about 2 weeks now.Woke up this morning and powered it on and apple logo reached like 95% and screen went black and it started giving me very high fan spin.That is all it's doing now.When i plug power like after 15 seconds fans goes high.
I checked some voltage rails and realize CPU Vcore is missing.I get a slight heat on the PCH and it's pulling 0.35 milliamps on bench power supply.
Can you guys tell me or confirm that the PCH might be dead? Resistance on PPVCORE_S0_CPU seems low about 2 ohms
PP1V8_S0 = 1.8v
PP1V8_S0_CPU = 1.8v
PP1V5R1V35 MEM = 1.3v
PP1V5_S3RS0 = 1.35v
PP1V5 S0 = 1.5v
PP1V05_SUS =1.056v
PP1V05_S0 = 1.045v

PPVCORE_S0_CPU = 0v
PPVCCSA_S0 = 0.8v

[mon2]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

Hi. High fan spin is smc area and communication faults.

Any corrosion on the logic board? Clean it up with IPA.

What are the voltage to ground of the following?

SMBUS_SMC_5_G3_SCL
SMBUS_SMC_5_G3_SDA

[reformatt]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

Check the CPU_VIDSOUT, CPU_VIDSCLK, CPU_VIDALERT_L lines to U7400 for impedance and activity. SA voltage is for the power controller within the CPU, which in turn drives those datalines to control U7400 for Vcore. You might get lucky and find some corrosion in this area, but it's often a dead CPU.

[platinumsteel]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

Hi. High fan spin is smc area and communication faults.

Any corrosion on the logic board? Clean it up with IPA.

What are the voltage to ground of the following?

SMBUS_SMC_5_G3_SCL
SMBUS_SMC_5_G3_SDA

SMBUS_SMC_5_G3_SCL = 3.4V
SMBUS_SMC_5_G3_SDA = 3.4V Keeps Pulsing between 3.3v and 3.4v

CPU_VIDSOUT = 0.953V
CPU_VIDSCLK = 1.1v
CPU_VIDALERT_L = 1.1v

My apologies mon2 but I had forgot to mention in the post that Yesterday i had discovered a solder blob that must of strayed from me when i was working on the initial problem in the PPVIN_S5 area not to far.I found it right around the CPU_VIDSCLK Area. I can't believe i didn't take a picture of it.I just flicked it off.Maybe that was the culprit that caused this weird issue.In the picture below i have drawn in red where the solder ball was stuck at.

[mon2]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

What is the voltage of PPBUS_G3H ?

This thread is on topic:

https://boards.rossmanngroup.com/thr...o-power.61838/

Check the voltage of the clock @ Y5010.

[platinumsteel]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

PPBUS_G3H = 12.56v
Y5010
Pin 1 = 1.1V
Pin 3 = 1.3V

[mon2]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

Good readings.

Do you have normal magsafe lights ?

[platinumsteel]

Re: Macbook Pro A1425 820-3462 Missing PPVCORE_S0_CPU

Good readings.

Do you have normal magsafe lights ?

Yes my friend.Using original 80Watt Charger as well. It goes green. Then orange.