Board-Level Repair Guide
MacBook Pro 16" M1 Pro A2485
Board
Identification
| Parameter | Value |
|---|---|
| Model Identifier | MacBookPro18,1 / MacBookPro18,2 |
| Board Number | 820-02016 (T728 MLB) |
| EMC Number | EMC 3651 |
| SoC | Apple M1 Pro (T6000) — 8/10-core CPU, 14/16-core GPU |
| Unified Memory | 16GB / 32GB LPDDR5 (soldered, non-upgradeable) |
| SSD Controller | Integrated ANS2 in M1 Pro — NAND soldered |
| PMU | MAVERICK (MPMU) + CLVR + SPMU — Apple proprietary |
| USB-C/Thunderbolt | 3× Thunderbolt 4 (USB4) — CD3217 controllers (ACE2) |
| MagSafe | MagSafe 3 — CD3217 (WHAMOLA) dedicated port controller |
| Display | 16.2" Liquid Retina XDR — 3456×2234, ProMotion 120Hz, mini-LED |
| Schematic Reference | T728 MLB Rev X2728 — 153 pages |
M1 Pro Architecture Note: Unlike Intel Macs, the M1 Pro integrates CPU, GPU, Neural Engine, I/O controllers, and Secure Enclave on a single SoC. The PMU system uses Apple's custom MAVERICK (main PMU), CLVR (voltage regulators), and SPMU (sensor PMU). Traditional "SMC" functions are now handled by the AOP (Always-On Processor) within the SoC. USB-C port controllers remain CD3217 (ACE2) architecture.
Voltage
Rails
| Rail | Nominal | State | Regulator/Source | Schematic Page | Notes |
|---|---|---|---|---|---|
| PPBUS_G3H | 8.5–12.6V | G3H | Battery / MagSafe charger | 52 | Main power bus. If absent: check battery connector, MagSafe port, F7000 fuse |
| PP3V3_G3H | 3.3V | G3H | MAVERICK MPMU | 135 | Always-on 3.3V. If absent: MPMU not starting — check PPBUS_G3H input |
| PP1V8_G3H | 1.8V | G3H | MAVERICK MPMU | 135 | Always-on 1.8V for PMU logic. If absent: MPMU failure |
| PP5V_G3S | 5.0V | S5 | MAVERICK MPMU LDO | 136 | Standby 5V. If absent: check PM_SLP_S5_L signal from AOP |
| PP3V3_S5 | 3.3V | S5 | MAVERICK MPMU | 136 | S5 standby 3.3V. Powers CD3217 controllers. If absent: AOP not releasing sleep |
| PP1V8_S5 | 1.8V | S5 | MAVERICK MPMU | 136 | S5 standby 1.8V. If absent: check SPMU enable sequence |
| PP5V_S0 | 5.0V | S0 | CLVR Buck | 137 | Active 5V. If absent: system not exiting S5 — check power button signal |
| PP3V3_S0 | 3.3V | S0 | CLVR Buck | 137 | Active 3.3V. If absent: CLVR not enabled — check PM_SLP_S3_L |
| PPVDD_SOC_S0 | 0.75–1.1V | S0 | CLVR multi-phase buck | 15, 23 | SoC core voltage. Dynamic. If absent: SoC not requesting power — fatal |
| PPVDD_GPU_S0 | 0.7–1.0V | S0 | CLVR multi-phase buck | 15, 23 | GPU core voltage. If absent: GPU block disabled or shorted |
| PPVDDQ_S0 | 0.5V | S0 | CLVR | 18, 29 | LPDDR5 memory VDQ. If absent: memory controller failure |
| PP2V5_NAND | 2.5V | S0 | TPS62180 | 75, 83 | NAND flash power. CRITICAL: If TPS62180 shorts, 12V can destroy NAND! |
| PPVOUT_LCDBKLT | 38–55V | S0 | LP8557↗ boost | N/A (display) | Mini-LED backlight boost. If absent: no backlight — check BKLT_EN signal |
| PP5V_USB | 5.0V | S0 | LT8642 / TPS62180 | 75, 83 | USB VBUS. If absent: check load switch enable, fuse, or short on bus |
Critical TPS62180 Failure Mode: The TPS62180 buck converter (PP2V5_NAND creation) is notorious for failing short on A2141/A2485 boards. When it fails, it can send 12V+ directly to the soldered NAND flash, destroying all data. This is often the cause of "dead board + swollen battery" symptoms. See Short Circuit Methods for detection procedure.
Power
Tree
AC ADAPTER / BATTERY │ ├─PPBUS_G3H (8.5–12.6V) ────────────────────────────────────────────────────────── │ │ │ ├─MAVERICK MPMU ───────────────────────────────────────────────────────────── │ │ ├─ PP3V3_G3H (3.3V) ─── CD3217 USB-C controllers, PMU logic │ │ ├─ PP1V8_G3H (1.8V) ─── PMU internal, AOP standby │ │ ├─ PP5V_G3S (5.0V) ──── Sensor hub, always-on peripherals │ │ │ │ │ └─[S5 Domain — AOP alive, system "off"] │ │ ├─ PP3V3_S5 (3.3V) ─── USB-C PD negotiation, lid sensor │ │ ├─ PP1V8_S5 (1.8V) ─── AOP logic, Secure Element (CERES) │ │ └─ PP5V_S5 (5.0V) ──── Keyboard controller, Touch ID │ │ │ ├─CLVR (Clever Voltage Regulators) ──────────────────────────────────────── │ │ │ │ │ └─[S0 Domain — System running] │ │ ├─ PP5V_S0 (5.0V) ──────── SSD, USB, audio codec │ │ ├─ PP3V3_S0 (3.3V) ─────── PCIe, SD card, HDMI │ │ ├─ PP1V8_S0 (1.8V) ─────── I/O, eDP, MIPI │ │ ├─ PPVDD_SOC_S0 (0.75–1.1V) ─ M1 Pro CPU/GPU core │ │ ├─ PPVDD_GPU_S0 (0.7–1.0V) ── GPU dedicated power │ │ ├─ PPVDDQ_S0 (0.5V) ──────── LPDDR5 memory │ │ └─ PPVDD2H0/H1 (varies) ──── High-speed I/O rails │ │ │ ├─TPS62180 (USB-C 5V Regulator) ──────────────────────────────────────────── │ │ └─ PP5V_USB (5.0V) ─── USB VBUS power, Thunderbolt devices │ │ │ ├─TPS62180 (NAND Regulator) — CRITICAL FAILURE POINT ────────────────────── │ │ └─ PP2V5_NAND (2.5V) ─── Soldered NAND flash (data loss if shorted!) │ │ │ └─LP8557 Backlight Boost ────────────────────────────────────────────────── │ └─ PPVOUT_LCDBKLT (38–55V) ─── Mini-LED backlight driver │ └─MAGSAFE 3 PORT (WHAMOLA) └─ CD3217 ─── MagSafe negotiation, PPBUS_G3H charging path
Key
Components
| Reference | Designation | Function | Rails | Page | Common Failure |
|---|---|---|---|---|---|
| U1000 | Apple M1 Pro (T6000) | Main SoC — CPU, GPU, Neural Engine, I/O | PPVDD_SOC, PPVDD_GPU, PPVDDQ | 4–44 | Rarely fails; usually killed by upstream voltage overshoot |
| U7000 | MAVERICK MPMU | Main PMU — G3H/S5 rail generation | PPBUS_G3H → all G3H/S5 | 135–139 | No boot if damaged; check PPBUS_G3H input first |
| U7100 | CLVR Controller | Multi-phase VRM controller for SoC | PPVDD_SOC, PPVDD_GPU | 137 | SoC VCore missing; replace with matching mosfets |
| U7220 | CPU VRM Mosfet | High-side/low-side switch for VCore buck | PPVDD_SOC_S0 | 15, 23 | Shorts from liquid damage; sends 12V to SoC |
| U3100 | CD3217 (ATC0) | USB-C Port Controller — Thunderbolt 4 | PP3V3_G3H, PP3V3_S5 | 67–72 | No USB-C recognition; liquid damage common |
| U3200 | CD3217 (ATC1) | USB-C Port Controller — Thunderbolt 4 | PP3V3_G3H, PP3V3_S5 | 68, 72 | Port dead; check CC protection circuit |
| U3300 | CD3217 (ATC2) | USB-C Port Controller — Thunderbolt 4 | PP3V3_G3H, PP3V3_S5 | 77, 80 | Right-side port failure |
| U3500 | CD3217 (MagSafe/WHAMOLA) | MagSafe 3 Port Controller | PP3V3_G3H | 55–56 | No charge via MagSafe; USB-C may still work |
| U7500 | TPS62180 (NAND) | PP2V5_NAND buck converter | PPBUS_G3H → PP2V5_NAND | 75, 83 | CRITICAL: Fails short, sends 12V to NAND = data loss |
| U7600 | TPS62180 (USB 5V) | PP5V_USB buck converter | PPBUS_G3H → PP5V_USB | 75, 83 | USB devices not powered |
| U8100 | Secure Element (CERES) | SEP ROM, Touch ID pairing | PP1V8_S5 | 26, 50 | Touch ID fails; Apple pairing required |
| U9000 | HDMI MADEA | HDMI 2.0 retimer/controller | PP3V3_S0 | 86–90 | No HDMI output; check enable signal |
| U9100 | GL9755 (SD Card) | SD Card controller | PP3V3_S0 | 91–92 | SD slot not working; often liquid damage |
| F7000 | PPBUS Main Fuse | Main power fuse — PPBUS_G3H | PPBUS_G3H | 52 | Open = no power at all; check continuity |
Angle Sensor Calibration (M1 Series): Unlike Intel Macs, the M1 Pro's angle sensor (lid position) is calibrated to the logic board via Apple Configurator 2 or GSX. Swapping screens or disconnecting the angle sensor flex cable can cause "black screen on lid open" — the sensor reports lid closed. Recalibration requires Apple software tools. See video transcript: "I think sensor got dis-calibrated when I tried to swap the screen."
Boot
Sequence
| # | Signal / Rail | Expected Value | Condition | If Absent |
|---|---|---|---|---|
| 1 | PPBUS_G3H | 8.5–12.6V | Battery connected or charger attached | Check battery connector seating, F7000 fuse continuity, MagSafe CD3217 enable. Measure PPBUS_G3H to GND resistance — <2Ω = short on bus → DC injection |
| 2 | PP3V3_G3H | 3.3V | PPBUS_G3H present | MAVERICK MPMU not starting. Check PPBUS_G3H input to U7000. If PPBUS present but 3V3_G3H absent: MPMU damaged or shorted output — measure 3V3_G3H to GND (<5Ω = short) |
| 3 | PP1V8_G3H | 1.8V | PP3V3_G3H present | MPMU internal LDO failure. Check for liquid damage around U7000. If 3V3_G3H OK but 1V8_G3H absent: MPMU needs replacement |
| 4 | CD3217 negotiation | 20V @ charger | PP3V3_G3H present | USB-C charger stuck at 5V: CD3217 not powered or damaged. Check PP3V3_G3H at U3100 VDD pins. If voltage present but no 20V negotiation: CD3217 failure |
| 5 | PP3V3_S5 | 3.3V | AOP releases SLP_S5_L | AOP (SMC equivalent) not alive. Check for short on PP3V3_S5 bus (<3Ω = shorted peripheral). Common: liquid on CD3217, keyboard flex, Touch ID connector |
| 6 | PP5V_S5 | 5.0V | PP3V3_S5 present | Keyboard/Touch ID not powering on. Check MPMU S5 LDO enable. If 3V3_S5 OK but 5V_S5 absent: measure 5V_S5 to GND for short |
| 7 | PWRBTN_L asserted | Goes LOW | Power button pressed or lid opened | Power button flex cable damaged, Touch ID module failure, or AOP not recognizing input. Check power button continuity, Touch ID connector seating |
| 8 | PM_SLP_S5_L | Goes HIGH | AOP initiates S5→S0 transition | AOP stuck in S5. Check for pending DFU mode, kernel panic log via Apple Configurator. If no software issue: AOP/SoC failure — board likely dead |
| 9 | PP5V_S0 | 5.0V | PM_SLP_S5_L HIGH | CLVR not enabling S0 rails. Check PM_SLP_S3_L signal. If S5 rails OK but S0 absent: CLVR controller failure or shorted S0 load (SSD, PCIe) |
| 10 | PP3V3_S0 | 3.3V | PP5V_S0 present | PCIe/SD card peripheral not powered. Check for short on PP3V3_S0 bus. SD card slot liquid damage is common cause |
| 11 | PPVDD_SOC_S0 | 0.75–1.1V | CLVR VRM enabled | SoC not receiving core voltage — fatal. Check U7100 CLVR controller enable, measure VCore inductor output. If 0V: CLVR or VRM mosfets (U7220) failed. If <0.5Ω to GND: shorted mosfet → DC injection on VCore |
| 12 | PPVDDQ_S0 | 0.5V | SoC initializing memory | Memory VDQ rail missing — SoC will not boot. Check CLVR VDDQ regulator. If soldered LPDDR5 is shorted, board is BER (beyond economical repair) |
| 13 | PP2V5_NAND | 2.5V | S0 active | NAND not powered — no boot, question mark folder. Check TPS62180 (U7500). If 0V at output but PPBUS present: TPS62180 dead. If <1Ω to GND: TPS62180 shorted → DATA LOSS LIKELY |
| 14 | SoC POST complete | Fan spin, chime | All S0 rails stable | No fan spin: SoC not executing. Connect to Apple Configurator — attempt DFU restore. If DFU not recognized: SoC/memory failure |
| 15 | PPVOUT_LCDBKLT | 38–55V | Display initialized | Backlight boost not switching. Check BKLT_EN signal from display timing controller. If EN present but no boost: LP8557 or boost inductor failed. See No Backlight |
| 16 | Display image | Apple logo | Backlight + eDP active | Backlight present but no image: eDP signal failure, TCON, or panel. Try external display. If external works: display flex, TCON, or panel issue |
M1 Pro Boot Behavior: Unlike Intel Macs, M1 machines do not produce traditional SMC beep codes. Boot failure manifests as: (1) no fan spin, (2) no chime, (3) black screen. Diagnosis requires USB-C connection to another Mac running Apple Configurator 2 to access DFU mode and revive/restore firmware.
Interactive
Diagnostic Engine
Work through stages in order. Complete each stage before unlocking the next. This 6-stage flow replicates expert technician reasoning for M1 Pro A2485 board diagnosis.
1
Always-On Rails (G3H / Power Source)
Expand ▼
2
Standby Rails (S5 / AOP alive)
🔒 Complete Stage 1 first
3
Active Rails (S0 / System Running)
🔒 Complete Stage 2 first
4
Core Voltages (SoC / Memory)
🔒 Complete Stage 3 first
5
I/O & Display (Backlight / NAND)
🔒 Complete Stage 4 first
6
Peripheral / USB (Thunderbolt · SD · HDMI)
🔒 Complete Stage 5 first
No Power /
No Charge
A2485 No Power — Initial Assessment
The MacBook Pro 16" M1 Pro (A2485) uses a fundamentally different power architecture than Intel Macs. There is no traditional SMC chip — the AOP (Always-On Processor) inside the M1 Pro SoC handles power management. The MAVERICK MPMU generates always-on and standby rails.
Before proceeding: M1 Macs require Apple Configurator 2 for DFU restore. Many "no power" symptoms are firmware-related and can be resolved by connecting to another Mac and performing a revive or restore. Always attempt software recovery before board-level diagnosis.
No Power — Symptom Categories
- No LED on MagSafe, no USB-C negotiation (stuck at 5V)
- PPBUS_G3H absent — check battery connector, F7000 fuse
- Measure PPBUS_G3H to GND: <2Ω = short circuit → DC injection
- If battery OK but MagSafe dead: CD3217 (U3500 WHAMOLA) failure
- MagSafe LED lights, USB-C negotiates 20V, but no boot
- PP3V3_G3H and PP3V3_S5 should be present
- AOP is alive but not transitioning to S0
- Check PM_SLP_S5_L signal — should go HIGH on power button
- Try DFU mode: connect to another Mac, hold power button for 10+ seconds
- Fan spins briefly then stops
- SoC starting but failing POST
- Check PPVDD_SOC_S0 — VCore may be collapsing under load
- Check PP2V5_NAND — if NAND shorted, boot aborts
820-02016 PPBUS_G3H Missing — Diagnostic Flow
| Step | Action | Expected | If Fail |
|---|---|---|---|
| 1 | Measure battery voltage directly at connector | 11.1–12.6V | Dead battery or battery not seating (screwed connector) |
| 2 | Check F7000 fuse continuity | 0Ω | Open fuse = prior short event; check for cause before replacing |
| 3 | Measure PPBUS_G3H to GND resistance | >50Ω | <2Ω = short on PPBUS → DC injection to locate |
| 4 | Check MagSafe connector for debris/damage | Clean, no bent pins | Damaged connector = no charge path; replace MagSafe board |
| 5 | Check CD3217 (U3500) MagSafe controller | Receives PP3V3_G3H | If 3V3_G3H present but no charge: U3500 dead |
A2485 Swollen Battery + Dead Board — TPS62180 Failure
This is the signature failure mode of A2141/A2485 boards. A swollen battery often indicates the TPS62180 (U7500) has failed short, causing:
- PPBUS_G3H short to ground (pulls excessive current)
- Battery overloaded, expands (airbag deployed)
- 12V+ sent to NAND flash, destroying data
Data Loss Warning: If TPS62180 failed short, there is a high probability that 12V was sent to the soldered NAND. Data recovery is NOT possible if NAND is destroyed. This is a common, unfixable failure mode on M1 MacBook Pros.
Diagnostic sequence:
- Remove swollen battery (fire hazard)
- Measure PPBUS_G3H to GND — if <1Ω, short present
- Measure PP2V5_NAND to PPBUS_G3H — if <10Ω, TPS62180 is shorted
- Remove TPS62180 (U7500) — short should clear
- Replace TPS62180 with known-good part
- If question mark folder on boot: NAND destroyed — board is BER
No
Backlight
A2485 No Backlight — Boost Circuit and Enable Signal
The A2485 uses a mini-LED backlight with local dimming zones. The backlight driver is an LP8557 or similar boost converter that generates 38–55V for the LED strings.
No Backlight — Symptom Categories
- Black screen, no Apple logo visible (even with flashlight)
- Total display failure — check eDP power rail (PP3V3_LCDVDD)
- If eDP power present but no image: TCON or panel failure
- Faint image visible with flashlight, but no backlight
- Backlight boost not switching
- Check BKLT_EN signal from display timing controller
- Check boost IC input voltage (PPBUS_G3H or PP5V_S0)
- Backlight works on external display, not on internal
- Display flex cable damage (very common on A2485 — fragile)
- Backlight fuse on display board (not logic board)
Backlight Boost Circuit — Checkpoints
| Component | Test Point | Expected | If Fail |
|---|---|---|---|
| Boost IC VIN | Input cap | 5V or PPBUS | Check upstream rail; if missing, system not in S0 |
| BKLT_EN | Boost IC enable pin | 3.3V when display active | If 0V: SoC not sending enable — software/firmware issue |
| Boost inductor output | L_BKLT output | 38–55V | If 0V and EN present: boost IC or inductor failure |
| Backlight connector | Display board input | 38–55V | If boost present but connector 0V: fuse on display board |
820-02016 Angle Sensor — Lid Open Detection Failure
M1 Angle Sensor Calibration: Unlike Intel Macs that use a simple Hall-effect lid sensor, M1 Macs use an angle sensor (CDS3017 or similar) that is calibrated to the logic board. Swapping screens or disconnecting the angle sensor flex cable can cause "black screen on lid open" — the system reports the lid as closed even when open.
Symptoms of angle sensor failure:
- Screen stays black when lid opened, but works when connected to external display
- System wakes momentarily (Apple logo visible) then immediately sleeps
- Magnet test: placing a magnet near the angle sensor location triggers wake/sleep erratically
Resolution:
- Check angle sensor flex cable for damage (liquid corrosion common)
- Re-seat angle sensor connector on logic board
- If flex cable damaged: requires Apple Configurator 2 / GSX to re-calibrate after replacement
- Independent repair shops cannot recalibrate angle sensor without Apple tools
Liquid
Damage
A2485 Liquid Damage — Assessment and Recovery
Liquid damage on A2485 typically affects the following areas due to board layout and common spill patterns:
- USB-C ports (left side) — CD3217 controllers, PP3V3_S5 shorts
- Keyboard flex connector — S5 rail shorts, no boot
- SD card slot — PP3V3_S0 shorts
- CPU VRM area — U7220 corrosion → 12V to SoC (fatal)
Liquid Damage — Triage Protocol
| Step | Action | Purpose |
|---|---|---|
| 1 | Visual inspection under microscope (10–20×) | Identify corrosion, solder balls, burnt components |
| 2 | Check Apple liquid damage indicators (LDIs) | White = dry, Pink/Red = liquid contact (humidity or spill) |
| 3 | Measure PPBUS_G3H to GND resistance | Detect main power bus short |
| 4 | Measure PP3V3_S5 to GND resistance | Detect standby domain short (common with keyboard liquid) |
| 5 | Ultrasonic clean in IPA/distilled water | Remove corrosion before power-on |
| 6 | Reflow/replace corroded components | Fix shorts and restore function |
Common Liquid Damage Failures — A2485
- CD3217 (U3100/U3200/U3300) — corrodes easily; causes "USB-C not charging" or "stuck at 5V"
- Keyboard flex connector — liquid wicks up flex; shorts PP3V3_S5 or PP5V_S5
- TPS62180 (U7500) — if liquid reaches this area, can cause failure short and NAND destruction
- U7220 (CPU VRM mosfet) — corrosion causes solder balls to form; mosfet fails short → 12V to SoC
Solder Balls as Indicator: Visible solder balls near a component often indicate that component overheated or failed. On A2485, solder balls near U7220 (CPU VRM) or U7500 (TPS62180) are strong indicators of the failure location. As Louis Rossmann notes: "Those solder balls over there... that usually means there was heat in that area or that thing could have blown up."
Short
Circuit Methods
820-02016 Short to Ground — DC Injection Method
When a rail measures low resistance to ground (typically <2Ω for PPBUS, <5Ω for 3V3 rails), a component is shorted. The goal is to identify which component by injecting controlled current and detecting heat.
Critical Warning — M1 SoC Protection: The M1 Pro SoC can be destroyed by overvoltage. When short-detecting on A2485, NEVER exceed 1V injection voltage. Start at 0.5V and increase slowly. The lowest rail voltage in the system is ~0.5V (PPVDDQ). If a VRM mosfet is shorted, higher injection voltage will send that voltage directly to the SoC.
DC Injection PSU Settings — A2485
| Rail | Injection Voltage | Current Limit | Max Duration | Notes |
|---|---|---|---|---|
| PPBUS_G3H | 1.0V | 3A | 30 sec | Inject at F7000 fuse pad; feel for heat on buck converter ICs |
| PP3V3_G3H | 1.0V | 2A | 30 sec | Check CD3217 controllers for heat |
| PP3V3_S5 | 1.0V | 2A | 30 sec | Disconnect keyboard flex; if short clears, keyboard IC is cause |
| PP5V_S0 | 1.0V | 2A | 30 sec | Remove SSD module if installed; check for external short |
| PPVDD_SOC_S0 | 0.5V | 5A | 15 sec | VRM mosfet (U7220) area; if U7220 hot, mosfet shorted |
| PP2V5_NAND | 1.0V | 2A | 20 sec | TPS62180 (U7500) is primary suspect |
Method A: DC Injection + Finger/Face Detection
- Remove heatsink and battery
- Connect PSU ground to board ground (any ground pad)
- Connect PSU positive to the shorted rail (fuse pad or large cap)
- Set voltage per table above; set current limit
- Enable output; use finger (or face if more sensitive) to feel for heat
- Shorted component will get warm within 5–15 seconds
- Disable output immediately once located to prevent damage
Method B: Thermal Camera Detection
- Same setup as Method A
- Use FLIR or thermal camera pointed at board
- Enable output; watch for hot spot on camera
- Advantage: faster, non-contact; Disadvantage: camera software can be finicky
Method C: Divide and Conquer
For complex shorts affecting multiple potential components:
- Identify all components connected to the shorted rail (use boardview)
- Remove one component at a time, re-measuring resistance after each
- When resistance returns to normal, last removed component was the short
- Useful when thermal detection is inconclusive
A2485 VRM Mosfet Short — U7220 Replacement
If the shorted component is U7220 (CPU VRM mosfet), you must replace BOTH the mosfet AND the controller (U7100) as a pair. Rationale from Louis Rossmann:
"What if it kills the controller? If it kills this chip which is the controller chip, then that means that the controller chip may be dead which means that the controller chip is then going to kill my new chip that I just placed on this board... I am not just going to replace that one component in the buck converter... we are going to replace both chips."
- Remove U7220 (QFN package)
- Clean pads; check for lifted traces
- Remove U7100 controller
- Clean controller pads
- Install donor U7100 first, then donor U7220
- Verify PPBUS_G3H short is cleared before applying power
- Verify PPVDD_SOC_S0 short is cleared
- Apply power; check for SoC VCore presence
Measurement
Points
| Rail / Signal | Test Point Location | Expected Value | GND Resistance (Unpowered) |
|---|---|---|---|
| PPBUS_G3H | F7000 fuse top pad | 8.5–12.6V | >50Ω (normal), <2Ω = short |
| PP3V3_G3H | C7010 top (MPMU area) | 3.3V | >100Ω (normal), <5Ω = short |
| PP1V8_G3H | C7050 top | 1.8V | >200Ω (normal), <10Ω = short |
| PP3V3_S5 | C3100 top (near CD3217) | 3.3V | >50Ω (normal), <3Ω = short |
| PP5V_S5 | C7200 top | 5.0V | >30Ω (normal), <2Ω = short |
| PP5V_S0 | C7300 top | 5.0V | >20Ω (normal), <2Ω = short |
| PP3V3_S0 | C7350 top | 3.3V | >30Ω (normal), <3Ω = short |
| PPVDD_SOC_S0 | L7100 output | 0.75–1.1V | >2Ω (normal), <0.5Ω = VRM short |
| PPVDDQ_S0 | C7500 top | 0.5V | >5Ω (normal), <1Ω = memory short |
| PP2V5_NAND | C7600 top | 2.5V | >20Ω (normal), <1Ω = TPS62180 short |
| PP5V_USB | USB-C VBUS cap | 5.0V | >10Ω (normal), <2Ω = short |
| PPVOUT_LCDBKLT | Backlight inductor output | 38–55V | >1kΩ (normal), <100Ω = boost short |
Required
Tools
Multimeter
Fluke 87V or equivalent; 4-digit precision for low voltage measurements
USB-C PD Trigger/Ammeter
YZXStudio ZY1280 or similar; monitor voltage negotiation and current draw
Bench Power Supply
0–30V, 0–5A; adjustable current limit essential for DC injection
Hot Air Rework Station
Quick 861DW or JBC; 100–500°C; BGA/QFN removal capability
Microscope
10–45× stereo zoom; AmScope or Mantis; essential for QFN inspection
Thermal Camera (Optional)
FLIR ONE or similar; accelerates short detection
Boardview Software
OpenBoardView with A2485/820-02016 boardview file
Ultrasonic Cleaner
Branson or Crest; IPA or distilled water; liquid damage recovery
Pentalobe P5 Screwdriver
Bottom case screws on A2485
Torx T3 / T5 Screwdrivers
Internal screws, battery connector
Apple Configurator 2
Required for DFU restore on M1 Macs; runs on another Mac
Donor Boards
A2485/A2141 donors for TPS62180, U7220, CD3217 harvesting
Frequently Asked
Questions
What is the most common failure on the MacBook Pro 16" M1 Pro A2485?
The most common failure is the TPS62180 (U7500) NAND power regulator failing short. This sends 12V+ to the soldered NAND flash, destroying all data. Symptoms include: PPBUS_G3H short to ground, swollen battery, and question mark folder on boot. This failure is often irreparable because the NAND is soldered and data cannot be recovered once destroyed.
Why does my A2485 show a swollen battery and no power?
A swollen battery combined with no power strongly suggests the TPS62180 NAND regulator has failed short. The short causes excessive current draw from the battery, which overheats and expands. Remove the battery immediately (fire hazard) and measure PPBUS_G3H to GND — if less than 2Ω, the TPS62180 is likely the cause. Replace U7500, but be prepared for data loss if 12V reached the NAND.
Can I replace the SSD on an M1 Pro MacBook Pro?
No. The NAND flash on M1 MacBook Pros is soldered directly to the logic board and is encrypted/paired to the T2-equivalent security in the M1 chip. There is no socketed SSD module. If the NAND is destroyed by overvoltage from a TPS62180 failure, the data is unrecoverable and the board is considered BER (beyond economical repair) for data-dependent users.
How do I diagnose "no power" on an M1 Mac without traditional SMC signals?
M1 Macs do not have a traditional SMC chip. The AOP (Always-On Processor) inside the M1 SoC handles power management. Start by checking PPBUS_G3H (battery power), then PP3V3_G3H (MAVERICK MPMU output). If both are present, check if USB-C negotiates 20V. If 20V is achieved, the CD3217 controllers are working. Then check S5 rails (PP3V3_S5, PP5V_S5) and S0 rails (PP5V_S0, PP3V3_S0, PPVDD_SOC). Use Apple Configurator 2 to attempt DFU restore — many "no power" issues are firmware-related.
What causes "screen black on lid open but works on external display" on A2485?
This is typically caused by angle sensor failure or miscalibration. M1 Macs use a calibrated angle sensor (not a simple Hall-effect lid switch) that is paired to the logic board. Swapping screens or liquid damage to the angle sensor flex cable can cause the system to report the lid as closed. Resolution requires re-calibration via Apple Configurator 2 or GSX, which is not available to independent repair shops.
What tools are required for A2485 board-level repair?
Essential tools include: a USB-C PD ammeter to monitor charging negotiation, a bench power supply (0–30V, 5A) for DC injection short detection, a hot air rework station for BGA/QFN removal, a stereo microscope (10–45×), OpenBoardView with the 820-02016 boardview file, and Apple Configurator 2 on another Mac for DFU restore. Donor boards (A2485 or A2141) are critical for harvesting TPS62180, CD3217, and VRM components.
Is liquid damage on A2485 repairable?
Liquid damage on A2485 is often repairable if caught early and cleaned properly. Common damage areas include CD3217 USB-C controllers, keyboard flex connector (shorts PP3V3_S5), and the SD card slot. However, if liquid reaches the CPU VRM area (U7220) or the TPS62180, the resulting short can send 12V to the SoC or NAND, causing fatal damage. Ultrasonic cleaning in IPA, followed by component-level diagnosis using the 6-stage diagnostic engine, offers the best chance of recovery.