17ips72: Schematic

If you find a file named 17ips72_NM-D811_r1.0.pdf, verify its hash or compare page count. A typical Lenovo Compal schematic has 52 pages. Any file with fewer than 30 pages is likely incomplete or a fake.

Scenario: A Lenovo Legion 5 17ACH6 with motherboard marking 17IPS72 REV 1.0. Symptoms: No power, no charging LED, barrel jack gets warm.

Step 1 – Visual inspection
Using the boardview, locate PF1 (fuse near DC-in). It is open. Replace it – still dead.

Step 2 – Voltage injection
Schematic indicates the main 20V rail splits into +VBUS and +VAD. Using a thermal camera, +VAD shows a hot spot at PC101 (0.1µF, 25V cap). Remove it – short gone. 17ips72 schematic

Step 3 – Check charger IC
BQ24780S has no REGN (6V). Schematic shows REGN requires 20V on ACDET (pin 5). ACDET reads 2.8V (should be >2.6V). Replace voltage divider RA1/RA2 (1MΩ and 120kΩ) – now ACDET = 3.1V. REGN appears.

Step 4 – 3V/5V missing
Schematic shows +3VALW generated by TPS51285 (U2). Enable signal EN1 (pin 3) is low. Trace EN1 through a diode to EC. EC is dead due to liquid damage. Replace EC (IT8227VG-192) – +3VALW rises.

Step 5 – Power on sequence
Laptop now powers on but no display. Using schematic, verify VDD_CORE = 0.9V, VDD_GFX = 0V. PGOOD from GPU VR is missing. Replace MP86945 driver – fixed. Laptop posts. If you find a file named 17ips72_NM-D811_r1

Without the 17ips72 schematic, this repair would be impossible in under 6 hours.

The 17ips72 schematic is a compact, component-dense design that balances analog front-end signal conditioning with a tightly integrated digital control section. It reads like a mixed-signal board intended for precision measurement or sensor interfacing: low-noise analog inputs, careful power-rail partitioning, and a microcontroller-driven acquisition/control domain.

| Symptom | Likely Cause | Schematic Pages to Check | |---------|--------------|--------------------------| | No power, no LED | DC-in mosfet failure (PQ1/PQ2) | Page 60 (Charger) | | Power cycles every 2 seconds | +1.35V_DDR missing or shorted | Page 22 (Memory power) | | Turns on, no display | GPU power sequencing failure | Page 28-30 (NVVDD, FBVDDQ) | | USB-C not working | TPS65982 firmware corrupted | Page 38 (Thunderbolt) | | Keyboard backlight stuck on | IT8226G I/O fault | Page 53 (KBC) | | Fans always 100% | EC missing temperature sensor data | Page 66 (Fan tach) | Scenario: A Lenovo Legion 5 17ACH6 with motherboard

Example: Battery indicator blinks white, but Windows says “Plugged in, not charging.”
Schematic fix: Turn to the USB-C PD page. Probe:

Replace the TPS65994 and the 0.3Ω resistor (RP602) — the schematic lists its exact value.

When troubleshooting "no power" or "no boot," use this order: