| Pin Group | Pin Numbers (Typical) | Function | Signal Type | |-----------|----------------------|----------|--------------| | Power Input | 1, 2, 35, 36 | Vcc (5V logic) & Vm (12V motor supply) | Power | | Charge Pump | 5, 6 | CP1, CP2 – external capacitor connections | Analog | | Phase U Out | 14, 15 | U+ (high-side), U- (low-side return) | Output | | Phase V Out | 17, 18 | V+ / V- | Output | | Phase W Out | 20, 21 | W+ / W- | Output | | Current Sense | 23, 24 | ISENSE – external resistor to GND | Analog | | Hall Emulation | 26, 27, 28 | H1, H2, H3 – synthesized Hall signals | Output | | FG (Speed) | 30 | Frequency Generator – tachometer pulse | Open drain | | RD (Lock) | 31 | Rotation Detect – high when motor at target speed | Open drain | | PWM/Reference | 32 | VREF – speed control voltage input | Analog | | Brake/Enable | 33 | BRK – active high brake | Digital |
The board generates several regulated low-voltage outputs, typically +3.3V (standby), +5V , and +12V . 17ips72 schematic work
If you cannot flash the BIOS, probe these pins. A stuck-low WP# (tied to ground via a weak pull-down resistor) is a common hidden fault. | Pin Group | Pin Numbers (Typical) |
By understanding its internal power stages, charge pump requirements, phase output logic, and diagnostic signals, you can confidently repair spindle motor failures that would otherwise be declared “unrecoverable.” By understanding its internal power stages, charge pump
View a detailed PDF schematic of the PFC controller circuit on specific symptoms
Assuming 3.3V and 5V are present, press the power button. Does PWRBTN#_EC toggle? Probe pin 36 of the EC (IT8226VG). No toggle? Bad power button board (check connector JEC1 using boardview).