boardrepair.me · Schematic reference
MacBook Pro A1989
Schematics and BoardView files for this board are not hosted here. See the sourcing card below for legal references, and our editorial standards for context.
Board overview
MacBook Pro 13" Touch Bar (2018–2019), board number 820-01700. Intel 8th generation Whiskey Lake (Core i5/i7). Fully USB-C design with 4 × CD3217 controllers. Apple T2 chip (T8012) handles SMC, SSD encryption, and boot security. ISL9239C fast-charge controller. Includes BoardView (.brd) and PDF schematic.
CPU / GPU
Intel Core i5/i7 8th gen (Whiskey Lake)
PMU / Charger
ISL9239C (charger), T8012 (T2 SMC)
Connectivity
CD3217 × 4
Schematic ref.
820-01700 / 820-00850
Power rails reference
Rails listed in measurement priority order — start at the top. Each rail must be present before the next can be generated.
| Rail name | Voltage | Notes & fault hints |
|---|---|---|
PPBUS_G3H |
12.6 V | Main bus rail from ISL9239 or battery. First measurement point. No PPBUS = no boot, no charging possible. |
PP3V3_G3H |
3.3 V | Always-on 3.3 V derived from PPBUS. Powers T2 and standby logic even when 'off'. |
SMC_BC_ACOK |
3.3 V | Adapter detected signal. Generated by ISL9239, received by T2/SMC. Critical for initiating charge sequence. |
PP3V3_S5 |
3.3 V | T2-generated standby rail. Absent = T2 not alive. Check PP3V3_G3H to T2 input. |
PP5V_S5 |
5.0 V | Standby 5 V. Powers USB-C VCONN when machine is sleeping. |
PP5V_S0 |
5.0 V | Active 5 V. Requires T2 S0 enable. Feeds Touch Bar, Touch ID, USB-C. |
PP3V3_S0 |
3.3 V | Active 3.3 V. Gated by T2. PCIe, NVMe, peripherals. |
PP1V8_S0 |
1.8 V | Active 1.8 V. CPU I/O, LP8557 backlight logic, display controller. |
Common failure zones
Most likely failures first. Each entry gives a symptom and the immediate diagnostic action.
No charging on any USB-C port
Measure PPBUS_G3H first. If present, test SMC_BC_ACOK with known-good cable+charger. Dead ISL9239 or T2 power domain fault.
No charging on one or two USB-C ports
CD3217 controller on affected side. Check CC lines. Very common after liquid ingress near left port cluster.
No power — PPBUS present, dead
T2 not initialising PP3V3_S5. Check PP3V3_G3H delivery to T2. Check T2 reset line. Liquid damage under T2 area.
Touch Bar not working
Touch Bar has separate power rails and serial communication. Check PPVDD_TOUCHBAR. Also check SPI/I2C bus from T2 to Touch Bar.
Backlight failure
LP8557 boost IC. Measure BLEN signal, PPBUS_G3H into LP8557. Check F9700-equivalent backlight fuse on A1989.