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This 820-02536 presented with areas of liquid damage in the R_SPKRAMP area near UN000. I removed two corroded caps that had shorted PPBUS_AON and PP1V25_AWAKE_NAND to ground. Now, connecting a charger gets PPBUS of 12.3V and 5.1 on USB-C. The charger gets to 20V but as soon as it does, the...

All tests were done with battery connected; that's how I found out that the board restarts with every plug/unplug of the charger cable. PPBUS is 12.3V, then as the Apple logo shows it drops to 12.0V. The startup process is interrupted by either USB-C resetting spontaneously, or by unplugging...

All three CD3217s show >1MΩ between PPVBUS_USBCx and PP5V_S2.

This A2681 2022 board came in with liquid damage in the PP5V_S2 area and some other small spots. After cleaning, I replaced a misbehaving UC300 and the machine now chimes and starts up. Trackpad and keyboard are nonfunctional, but I’ll troubleshoot that separately. The main issue is that...

Yes, but if the donor is a 256GB board, I'm ok transplanting just the SSD0 chips (four NANDs I think), right? I can leave the SSD1 slots empty?

Thanks. I assume if I do use a donor board, no initialization will be required?

This logic board had a shorted Ocarina power supply chip U9580. After replacing it, both NAND chips for SSD1 are getting hot and show multiple shorts to ground. It don't have a donor board at hand for NAND replacement. What's the best way to convert this board to only use SSD0 (I assume with...

I just saw that PMU_PVDDMAIN_EN is 150Ω to ground. A good board shows 45kΩ. I think the U7800 (PMU) I replaced from a donor board was bad and internally shorted on this pin. Will need to try another PMU.

This board has had prior work done on it; I expect it was liquid-damaged. Several power rails were shorted, which I fixed: replacement of U8510 removed a short on PP3V3_G3H_RTC, and replacing U7800 removed a short on PP3V3_G3H. PPBUS is 12.3V but briefly dips to 9V every second or so. No...

I just got my hands on a known good display and the camera works fine with it. So... liquid-damaged camera/ALS in the original screen.

Resistors are good. I replaced UD120/40 and UP420. No change. The LPDP_FTCAM_DATA bus remains at 0V even during camera access. Probably a bad display? it's just curious to see both camera and ALS both nonfunctional since they have separate data lines.

I currently don’t have a good display to test with. There was some liquid damage on the camera connector. After cleaning I verified that all pins are good (no shorts). Here's what I got so far: • 5V power rail goes to the display assembly • camera and ALS bus pins are at 1.8V • ALS_INT_L is...

I'm also trying to fix a non-responsive camera and ALS on this machine. Should I open a new thread?

I found two level shifters that weren't working: UT350 and UT320. Inputs for both were 1.25V but with 0V outputs. Replacing both of them from a donor board restored 3.3V on both outputs. Trackpad now clicks and tracks and the keyboard works as well. Your help is much appreciated!

All filters are checking out good. I'm going through the page 86 trackpad circuitry looking for failure points. What's the connection between trackpad and keyboard in this model?

Yup, one of the inputs to UC861 (PBUS_AONSW_IPD_FLT_L) was low, and 20Ω to ground. Replacement of UC861 removed the short and the fault is no longer there (IPD_OCP_FLT is 0V). However, there is still no response to the trackpad or the keyboard...

Ok, I went for replacing the MPMU with the correct subtype (343S00554) and functionality has been restored. Now back to getting the trackpad and keyboard to work. LT400 is good and at 12.3V. LT200 is good and at 1.8V. However, IPD_OCP_FLT is 1.8V, which means that a fault is asserted, correct?

13” and 15” as well?

I removed all BUCK output inductors from both PMUs and U8100 was still fluctuating. I then diode-mode checked all LDO outputs of both PMUs and found PP1V2_AON_MPMU at 5Ω to ground. Removal of U8100 removed the short. Thanks for helping troubleshoot this one. Can I source a replacement for the...

From the LDO OUTPUTS on pages 34 and 39 : some are stable (PP1V5_LDOINT_MPMU, PP1V8_AON_SPMU, PP1V2_AON_SPMU), some are fluctuating (PP1V8_AON, PP3V3_AON), and some are 0V (PP3V3_S2_LDO, PP1V2_S2_CIO, PP0V72_S2_VDD_LOW).