macbook a2251 820-01949a no power 20V ok

[reset1986]

hi all, this mac won't turn on, it seems that the battery is charged when I put the power supply, but there is no rotation of the fan and ignition,
I can't find shorts, I measured the 20V and they are ok

PP3V3_G3H 3.4v
PP5V_G3S 5v

PP3V3_G3H_RTC_REG_R 3.3V

l7030 12.25 rising,

i notice the l7030 gets warm but i think its normal for charging,

what could i check? Thank you

[mon2]

Re: macbook a2251 820-01949a no power 20V ok

What is the voltage to ground of PPBUS_G3H @ F7000 ?

[reset1986]

Re: macbook a2251 820-01949a no power 20V ok

What is the voltage to ground of PPBUS_G3H @ F7000 ?

f7000 11.30v with battery
with battery and power supply 11.80 and tends to go up

[mon2]

Re: macbook a2251 820-01949a no power 20V ok

According to:

https://repair.wiki/w/A2251_2020_13%22_MacBook_Pro

~12.60–12.65 V = Normal

So flux and remove F7000. Then check the voltage of this rail again on the PCB pads.

Post the measurement.

[reset1986]

Re: macbook a2251 820-01949a no power 20V ok

According to:

https://repair.wiki/w/A2251_2020_13%22_MacBook_Pro



So flux and remove F7000. Then check the voltage of this rail again on the PCB pads.

Post the measurement.

ok, removed, on one side 0, on the other 12.25, both with and without battery

[mon2]

Re: macbook a2251 820-01949a no power 20V ok

From the above repair wiki link:

~12.28–12.35 V = T2 communication issue with the ISL9240. The likely cause for this is the device is stuck in DFU mode due to corrupt T2 firmware or a failed CD3217. Proceed to repair steps below for corrupt T2 firmware.

[reset1986]

Re: macbook a2251 820-01949a no power 20V ok

From the above repair wiki link:

ok, I have an old imac with osx available, from what I've read, do you have to connect both macs with usb-c?

[piernov]

Re: macbook a2251 820-01949a no power 20V ok

Of course T2 won't communicate if PPBUS_G3H is disconnected.
Still T2 DFU recovery can be attempted if data is not important. (with the fuse in place obviously)
Also this voltage is only relevant when battery is disconnected as always.

[reset1986]

Re: macbook a2251 820-01949a no power 20V ok

Of course T2 won't communicate if PPBUS_G3H is disconnected.
Still T2 DFU recovery can be attempted if data is not important. (with the fuse in place obviously)
Also this voltage is only relevant when battery is disconnected as always.

ok,all the symptoms seems to have the t2 corrupted,i was wondering if it was possible to flash like on motherboards with external programmer