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Macbook Pro 16" M1 Pro A2485 820-02382

ipetro

ipetro

Member
I have this MacBook on my bench with the following issue:

The MacBook works perfectly fine on battery power, but as soon as I connect the charger and put the machine under load (for example, running Cinebench), the MacBook reboots.

I replaced Q5240 and U5200, and now the MacBook reboots under load—whether running on battery or the power adapter.


PPBUS_AON_REG=12.7V
PPDCIN_AON = 19.78 V (with adapter connected)
PP3V8_AON=3.8V
PP5V_S2_MAIN=5.15V
 
ipetro

ipetro

Member
The black probe is connected to ground, and the measurement is performed with the red probe:
C5220=17.27k on both sides
C5260=37,6 k on both sides
To perform the measurement, connect the black probe to pin 1 and the red probe to pin 2:
C5220=2.6 ohm
C5260 = 1,6 ohm

Here’s a quick update on what changed while I was waiting for a reply: I replaced U9300 and the MacBook started working properly, so I returned it to the client. However, a couple of days later, things got even worse: the MacBook would boot up to the Apple logo (sometimes even reaching the desktop) and then immediately shut down. This happened several times before it stopped turning on altogether; now, only the trackpad clicks. The USB meter shows 5V / 0.245A.
PPBUS_AON = 12.38V (board on the bench). PPDCIN_AON = 5v, PP3V8_AON=3.58-3.6v,PP5V_S2_MAIN=5.15V
 
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