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slimmy182 · 08-25-2025, 03:05 PM

Here’s the current status and all the checks done:

Power rails

Always-on / Awake:
- PP1V8_AWAKE ≈ 1.8 V (C2041) – stable
- PP1V2_AWAKE ≈ 1.2 V (C2040) – stable
- PP3V3_AON ≈ 3.3 V – present
- PP3V8_AON ≈ 3.8 V – present
- PPBUS_AON ≈ 12.3 V – present
CPU awake:
- PPVDD_ECPU_AWAKE ≈ 0.64 V idle, drops to 0 V during failed Revive
- PPVDD_ECPU_SRAM_AWAKE ≈ 0.77 V idle, drops to 0 V during failed Revive
Rails that appear only when Revive starts:
- PP1V2_S2 ≈ 1.2 V (CD102/CD103) – comes up
- PP3V3_S2 ≈ 3.3 V (CD150/CD151) – comes up
- PP1V8_S2 ≈ 1.8 V – comes up
SSD rails:
- PP2V5_NANDx

...

slimmy182 · 08-23-2025, 06:43 AM

Got

- PP2V5_NANDx ≈ 2.5 V
- PP1V2_NANDx ≈ 1.2 V
- PP0V9_NANDx ≈ 0.9 V

Just pop up when try to revive/restore...

slimmy182 · 08-23-2025, 02:46 AM

I replaced U2010 and U2020 with parts taken from a donor board.
Now I have:
PP1V2_AWAKE = 1.22 V
PP1V8_AWAKE = 1.77 V

In both cases, the Mac is detected in DFU mode by Apple Configurator, but when I try to restore it I get this error:
Unable to restore system on this device.
Unexpected device state 'DFU' expected 'Recovery' (Probably forced into DFU mode externally)
[com.apple.MobileDevice.MobileRestore – 0xFAE (4014)]

Any advice on what to check next would be greatly appreciated.However, the Mac still does not power on.
With the battery

...

slimmy182 · 08-21-2025, 02:35 PM

Checked resistor dividers / pull-ups (R2020–R2025, R2030–R2032, RD215, RD216, RR664, RR734) → PP1V8_AWAKE side low, signal side high.
Confirmed short not on SoC side of I²C lines (pin toward SoC always OL/high).
Removed UR600 (IC on the rail) → no change.
Began isolating speaker amp blocks:
- Removed UR700 → resistance rose to ~12 Ω.
- Removed UR730 → resistance rose further to ~32 Ω.
  - Checked its pads (pins 12, 18, 19, 23, 26, 27, 29, 30) → all OL/high.
- Finally removed UR760 → resistance became very high (rail clean).
  - All its pads OL/high → maybe UR760 itself internally leaky?

Current...

slimmy182 · 08-19-2025, 12:36 PM

Update:

After removing U2010, the resistance on PP1V8_AWAKE → GND increased from ~4 Ω to ~8 Ω.
Power injection at 1.5 V → ~0.15A (CV), no visible hotspot (thermal + IPA).
U2010 off-board: VCC–GND ≈ 6 Ω → clearly leaky; will replace.
U2000 off-board measured high resistance; reinstalled → rail still ~8 Ω.

slimmy182 · 08-18-2025, 01:04 PM

Thanks for the help so far. Here is what I tested today:

Removed and tested:
- C2021, C2030, C2041, C2010 → resistance unchanged (~4 Ω).
- U2030 & U2040 (SN74AVC1T45 level shifters) → resistance unchanged.
- LR501 / LR502 removed: on pin-2 side (codec rails) resistance is high; on pin-1 side (PP1V8_AWAKE) still ~4 Ω.
Injection test:
- Injected 1.5 V / 3 A into the rail (at C2041).
- With thermal camera + IPA, the only device that consistently shows activity under injection is U2010, which heats slightly (~40 °C, mostly on the upper side near C2010). (video attached)

What do you recommend...

slimmy182 · 08-16-2025, 03:43 PM

Sorry mon2, apologies — earlier I mistakenly reported PP1V8_AWAKE as ~0.40 Ω. That was incorrect (wrong scale/continuity mode).

Corrected measurements:

Probes short = 0.05 Ω.
PP1V8_AWAKE → GND = ~4.0 Ω (200 Ω range).
Power injection:
- 1.0 V / 3 A limit → ~0.2 A draw (CV).
- 1.5 V / 3 A limit → ~0.4 A draw (CV).
No clear hotspot with thermal cam or IPA during injection.

slimmy182 · 08-16-2025, 01:55 PM

Removed U2020 (SN74AVC2T45).
After removal, resistance PP1V8_AWAKE → GND @ C2021 is still ~0.40 Ω.
Injected ~1 V @ 1 A on PP1V8_AWAKE (C2021).
With thermal camera, U2010 warms up to ~40 °C, slightly hotter than surroundings, but nothing gets burning hot.

slimmy182 · 08-16-2025, 07:28 AM

Thanks for your advice mon2.

I checked the rails:

PP1V2_AWAKE = ~1.2 V (looks normal)
PP1V8_AWAKE = ~1.55 V (instead of 1.8 V)

With the board off, resistance to ground on PP1V8_AWAKE (measured at C2021 / C2030 / pin 8 of U2020) is about 004 Ω on my meter in continuity mode — basically the same as shorting the probes together.

Thank you!...

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MacBook M1 Pro 14" 2021 A2442 (820-02098) — U2020 getting hot, board not powering on