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Even with new NANDs same behavior.

Yeah it has another T2 chip, thanks for bringing it up.

So it’s fine? Proposed 16GB Config: MLB_RAMCFG0 = Low (1k ohm resistor to ground) MLB_RAMCFG1 = Low (1k ohm resistor to ground) MLB_RAMCFG2 = High (Pull-up / No resistor to ground) MLB_RAMCFG3 = Low (1k ohm resistor to ground) MLB_RAMCFG4 = Low (1k ohm resistor to ground)

Hi, I have upgraded the RAM on a test machine from 8GB to 16GB (SKhynix 9CCNNNBJTAL). What is the correct MLB_RAMCFG strap setting for this configuration? Proposed 16GB Config: MLB_RAMCFG0 = Low (1k ohm resistor to ground) MLB_RAMCFG1 = Low (1k ohm resistor to ground) MLB_RAMCFG2 = High...

I removed the NANDs, it still power cycles. (but now at 5V / 0.07A) I don’t think the issue is related to the NANDs. Even without NANDs, it should not power cycle.

Theoretically, the power-cycling issue should stop as soon as I remove the NAND chips and power on the device, right? If the same issue occurs, then the NANDs aren’t the problem or am I wrong?

So we can definitely rule out the power rails and sequencing as the main issue before moving on to the NAND task?

Says the same: https://openboarddata.org/?a=showboardsolutions&bpath=laptops/apple/820-02536 And another logicboard (working) has the same readings, so 3V8 can’t be the issue. (I mean 3.8V is also present)

0.328

what should I check next? Diode values of U8100/U7700 according to https://openboarddata.org/?a=showboardsolutions&bpath=laptops/apple/820-02536 are looking good.

But why are they so low?

Same behavior. But why is 3.8V wrong I mean the input is 3.8V (PP3V8_AON), shouldn’t be the output the same?

I have replaced L8430 with a known good one, still "MPMU_BSTLQ_LX" is at 3.8V. Note: - Measured both sides of L8430 on both sides 3.8V.

U8100: - MPMU_BSTLQ_LX: 0.326 / 3.8V - BUCK0_LX0: 0.091 / 0.6 - 1.0V - BUCK0_LX1: 0.091 / 0.6 - 1.0V - BUCK0_LX2: 0.091 / 0.6 - 1.0V - BUCK0_LX3. 0.091 / 0.6 - 1.0V - BUCK0_LX4: 0.091 / 0.6 - 1.0V - BUCK1_LX0: 0.006 / 0V - BUCK1_LX1: 0.006 / 0V - BUCK1_LX2: 0.006 / 0V - BUCK1_LX3: 0.006 / 0V -...

No fluctuation/spike visible on CHGR_A/BMON lines. Note: I measured at RD518 (CHGR_AMON) and RD528 (CHGR_BMON). Diode values: CHGR_AMON: 0.584 CHGR_BMON: 0.584

Without F5200 PPVBAT_AON_CHGR_REG is stable (12.26V)

Model: A2681 Board: 820-02536 Symptom (with charger only and battery/charger): The device continuously power loops between 5V and 20V (5V → 20V/0.01-0.12A → back to 5V → 20V/0.01-0.12A …). Measurements: PPBUS_AON: 12.26V → 11.97V → 6.6V → 12.26V ... not stable PP5V_AON: 5V stable PP3V8_AON...

Issue fixed - RC853 was blown, haptic feedback is now working. Note: PPBUS_AONSW_TPAD was missing. Regarding the audio issue, I replaced all three amplifier chips - cracking sound is gone.

Device is back online, trackpad feedback still not working (trackpad/keyboard is working)

All three?