Hi!
I'm an electronics student from Austria trying to fix a Macbook Pro A1707 from a friend of mine. He took it to an Apple store and they said it is a liquid damage and wanted to charge him 1300€ for a new logic board. Thus, he asked me if I could fix it. I have watched numerous videos from Louis on the "stuck at 5V" topic and started investiagting the issue
Here is a short summary of what I've done so far.
A visual inspection did not gave any obivous hints to a damaged part.
First I've checked the USB port and noticed that it got stuck at 5V and draws approx. 20mA. As suggested in multiple videos, I've measured the voltage rails around the ISL9239.
PPDCIN_G3H = 5V and is present at U7000,
PPBUS_G3H = ~0V
Then I've checked the supply rail of the USB-C port controllers, which was 0V.
--> PP3V3_G3H = ~0V
but the enable signal from U7000, PM_EN_P3V3_G3H was present. Thus, I've checked if PP3V3_G3H is shorted, which it was. As suggested in a video by Louis, it is very likely, that a CD3215 is responsible for this short, UB300. Thus, I've supplied 3.3V into the PP3V3_G3H rail and identified the faulty CD3215 with the "alcohol on chip" method. Then I desoldered this chip and the short on PP3V3_G3H was gone. I ordered a replacement and soldered it in.
However, the issue remained. The two ports, including the one I've fixed, stayed at constant 5V/20mA, but the other two ports did power cycle like in this video.
Louis replaced the TB SPI Flash chip in this video and resolved the issue. I was not sure if a fresh chip from Mouser will do the job or if it needs some pre flashed data. Anyway, I ordered fresh SPI Flash chips and gave it a shot. After I've desoldered U2890, these two USB-C ports did not power cycle any longer and this behavior persited after I soldered the fresh chip from mouser.
However, I've got stuck at this point and would need some further advice. First I've thought that the ISL9239 could be the problem, as PPBUS_G3H is not present, I've replaced it but it did not change anything. Could there be another faulty CD3215 or could it be a faulty SMC chip?
Board Rev.: 820-00928-A
Thanks in advance!
Kind regards
Michael
I'm an electronics student from Austria trying to fix a Macbook Pro A1707 from a friend of mine. He took it to an Apple store and they said it is a liquid damage and wanted to charge him 1300€ for a new logic board. Thus, he asked me if I could fix it. I have watched numerous videos from Louis on the "stuck at 5V" topic and started investiagting the issue
Here is a short summary of what I've done so far.
A visual inspection did not gave any obivous hints to a damaged part.
First I've checked the USB port and noticed that it got stuck at 5V and draws approx. 20mA. As suggested in multiple videos, I've measured the voltage rails around the ISL9239.
PPDCIN_G3H = 5V and is present at U7000,
PPBUS_G3H = ~0V
Then I've checked the supply rail of the USB-C port controllers, which was 0V.
--> PP3V3_G3H = ~0V
but the enable signal from U7000, PM_EN_P3V3_G3H was present. Thus, I've checked if PP3V3_G3H is shorted, which it was. As suggested in a video by Louis, it is very likely, that a CD3215 is responsible for this short, UB300. Thus, I've supplied 3.3V into the PP3V3_G3H rail and identified the faulty CD3215 with the "alcohol on chip" method. Then I desoldered this chip and the short on PP3V3_G3H was gone. I ordered a replacement and soldered it in.
However, the issue remained. The two ports, including the one I've fixed, stayed at constant 5V/20mA, but the other two ports did power cycle like in this video.
However, I've got stuck at this point and would need some further advice. First I've thought that the ISL9239 could be the problem, as PPBUS_G3H is not present, I've replaced it but it did not change anything. Could there be another faulty CD3215 or could it be a faulty SMC chip?
Board Rev.: 820-00928-A
Thanks in advance!
Kind regards
Michael
