Hello guys,
I have faulty 15" Macbook Pro 2012 with 820-3330-B motherboard with the following symptoms:
- when turned ON, there is a short increase in current to up to 0.8A (power supply unit display)and then back to zero.
- during this short time, one FAN try to spin (better to say vibrate).
I have done measurements on power rails and found that PP3v3_S0 is most likely shorted to ground. Multimeter readings are the following:
- 0.017 in diode mode (positive leas is on ground)
- 16 ohm t ground in resistance mode.
I'm pretty sure this is the culprit, but there are so many components connected to this power rail, and I don't have a thermal cam, so I wonder if it would be possible to find a faulty component by voltage injection
I have a lab PSU 0-30V, 0-5A. What would you recommend me to do? Where is the right spot to try to inject the voltage?
Thank you.
P.S: SMC is running (PPBus_G3H is 12.56 V), and there is PP3V42_G3H, since there is a green light on the charger.
I have faulty 15" Macbook Pro 2012 with 820-3330-B motherboard with the following symptoms:
- when turned ON, there is a short increase in current to up to 0.8A (power supply unit display)and then back to zero.
- during this short time, one FAN try to spin (better to say vibrate).
I have done measurements on power rails and found that PP3v3_S0 is most likely shorted to ground. Multimeter readings are the following:
- 0.017 in diode mode (positive leas is on ground)
- 16 ohm t ground in resistance mode.
I'm pretty sure this is the culprit, but there are so many components connected to this power rail, and I don't have a thermal cam, so I wonder if it would be possible to find a faulty component by voltage injection
I have a lab PSU 0-30V, 0-5A. What would you recommend me to do? Where is the right spot to try to inject the voltage?
Thank you.
P.S: SMC is running (PPBus_G3H is 12.56 V), and there is PP3V42_G3H, since there is a green light on the charger.
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