The ideea is to replace the optoma default fnas which are noisy with some quiet fans from Noctua or Noiseblocker

Optoma fans 70x70x25 mm with plastic spacers

Noiseblocker 80x80x25mm no spacers (59m3/H - 1,88mm H2O@2200RPM)

Noctua 80x80x25mm no spacers (50m3/H - 1,96mm H2O@2000RPM)

since the internal speed monitoring will require at least 1000 rpm or the projector will shut down i had to increase the fan voltage from +2V by adding a 680R resistence between the IC VSET line and the 12V (+) line.

This mod increases voltages :

Echo Mode 4v4 to 6v2 (1000RPM)

Bright 10.1 to 11.9v (2200 RPM)

Please note that the FAN controlers are NCT3941 and the datasheet can be found on the internet