Thanks, that's what I suspected.

I did end up removing U3100 and there was some damage around the pad for PP3V3_UPC_XA_LDO. I will attempt a repair later.

In the meantime, given that I have access to a bench power supply, is there a way I can provide power to the board directly to make the computer boot? I acknowledge that it would be a hassle to use it like so in the long run, but if at the very least I can boot it up once to recover some of the data on it in case something goes wrong with the repair later on.

Thanks! I've checked the page for the A1989 stuck at 5V on repair-wiki, R7900 does read 0R and R7075 does read 4R7 so both seem fine.

I'm going through the logic wiki guide for the CD3215, I've definitely been able to confirm that I get to step 7, I'm for now unsure how to check for the steps 8 and 9 for my specific board, I'll keep poking through the schematics and brd file to see if I can find my equivalents. I also know for a fact that I don't get to step 12 as my PP20V VBUS stays at 5.15V, so narrowing down the steps at which there might be an issue....

Here are all the measurements for each of the CD3215:[LIST][*]U3200 (XB):[LIST][*]PP20V_USBC_XB_VBUS: 5.15V[*]PP3V3_UPC_XB_LDO: 3.35V[*]PP1V8_UPC_XB_LDOD: 1.80V[*]PP1V8_UPC_XB_LDOA: 1.80V[*]PP1V1_UPC_XB_LDO_BMC: 1.12V[*]PPBUS_G3H: 12.3V[/LIST][*]UB400 (TB):[LIST][*]PP20V_USBC_TB_VBUS: 5.15V[*]PP3V3_UPC_TB_LDO: 3.35V[*]PP1V8_UPC_TB_LDOD: 1.80V[*]PP1V8_UPC_TB_LDOA: 1.82V[*]PP1V1_UPC_TB_LDO_BMC: 1.12V[*]PPBUS_G3H: 12.3V[/LIST][*]UB300 (TA):[LIST][*]PP20V_USBC_TA_VBUS: 5.16V[*]PP3V3_UPC_TA_LDO: 3.35V[*]PP1V8_UPC_TA_LDOD: 1.80V[*]PP1V8_UPC_TA_LDOA: 1.82V[*]PP1V1_UPC_TA_LDO_BMC: 1.12V[*]PPBUS_G3H: 12.3V[/LIST][/LIST]Regarding...

I am using a 96W Apple charger with its stock cable and have confirmed that it charges a different MacBook I have.

I will look into getting a bidirectional USB-C meter.

I do have another MacBook that I can try a DFU with, I had initially tried that before any repairs or cleanup but the laptop wasn't being detected. I will try again and report.

The battery of the laptop I'm repairing reads 0.2V, while I'm testing voltages and attempting a DFU:[LIST][*]Should the power connector of the battery be connected to the main board?[*]Should the FFC of the battery...

PPBUS_G3H is at 12.3V.

For the battery connector, both SMBUS_3V3_BATT_SDA and SCL are at 3.3V. The FFC to the battery is disconnected though, should I reconnect it?

In the meantime, I also payed close attention to the area that had the corrosion and did some measurements, and I noticed that I was getting a low voltage (around 0.2V) on pin 1 of C3100 which is PP3V3_G3H_RTC_ISOL, however what's interesting is that testing the same bus on different areas of the board did read 3.3V. I went ahead and removed C3100 (it does look slightly damaged upon closer inspection btw)....

Hey everyone!

I have a MacBook Pro A1989 with a 820-00850-A board that recently stopped working. I used it overnight to charge my phone, in the morning it didn't turn on, I assumed flat battery but now won't charge and doesn't start at all.

I have fully dissassembled it, when disconnected the battery reads at 0.012V. Even with the battery disconnected the laptop doesn't boot.

The diode voltages around all 4 CD3215's seem fine.

For all CD3215 (UB300, UB400, U3100 and U3200) I read just above 5V on PP20V_USBC_TA_VBUS, 3.3V on PP3V3UPC_TA_LDO, 1.8V...

Hey!

I have a bit of an unusual profile I think, I have both a bachelor's and master's degree in electronics engineering, however all of my professional career has been in software engineering, so most of my practical experience with electronics is from side projects and similar.

I've now started getting into repairs quite a bit and looking to level up into repairing more advanced hardware ...