Try these search strings (Google / Bing):
[DC-In Jack / Battery] ---> [VIN / DC-IN Rail (19.5V)] | [3.3V/5V Standby PWM] | +--------------------+--------------------+ | | | [3.3V_ALW] [5V_ALW] [1.35V_DDR] | | | (EC/BIOS) (USB/SATA) (RAM Power) | | +---------> [CPU Core VCC / System Rails] Primary Power Rails
: The ZBook uses a removable graphics module. Components near this slot, like the Q33 transistor , often fail. The schematic shows exactly what part to solder back into place. Tools Needed for Repairs
: It belongs to the HP ZBook 17 G3 Mobile Workstation . apw70 lac391p schematic portable
Verify secondary voltages like memory power or system agent rails. If the APW70 is responsible for generating these specific rails, check the FB (Feedback) loop to ensure resistors have not drifted in value. Step-by-Step Troubleshooting Process
The CPU PWM controller issues a SYS_PWROK or ALL_SYS_PWRGD signal back to the SoC, indicating that all voltages are flat and stable. The SoC then releases the hardware reset signal ( PLTRST# ), allowing the CPU to begin executing the BIOS code. 4. Common Failure Modes and Troubleshooting Strategies
Controlled by a dual-channel PWM controller, this circuit converts 19.5V into stable +3.3V and +5V rails. Key components to inspect on the schematic include: Try these search strings (Google / Bing): [DC-In
The APW70 LAC391P schematic has a wide range of applications in portable power solutions, including:
MXM slot for removable NVIDIA Quadro or AMD FirePro graphics. Memory: Typically 4x DDR4 SO-DIMM slots.
: If a battery is swollen or will not charge, tech experts use the schematic to verify the battery controller chips. They can check why the power rail is sending wrong signals to the battery connector pins. Tools Needed for Repairs : It belongs to
Intel Bay Trail-M (Celeron N2840, N2940, or Pentium N3540) soldered directly to the board.
Component-level technicians frequently encounter predictable failures on this specific Compal design: Faulty DC-In Protection MOSFETs
Two slots supporting up to 64 GB of DDR4 3200 MHz RAM.