| Pin Number |
Pin Name |
Description (may be empty) |
| 1 | Sense |
yellow // from fan |
| 2 | 12 V | red // fix voltage |
| 3 | GND | black |
| 4 | Speed | blue // from mainboard |
| 5 | NC | unused |
Measurements with CPU heat of 40°C:
Sense puls: ca. 27 Hz ( duty cycle 50:50), 3.3 V
Speed puls: ca. 2 usec and 43 usec pause, 3.3 V; probably a pwm puls