As of S/N 4217520001 we have implemented a filter circuit that further reduces noise from the 2 effect cooling fans in the MAC 2000 Profile when fan speed is reduced. Fan speed regulation was introduced in software version 1.8.
Full fan noise reduction can be implemented in earlier products by installing software version 1.8 and P/N 62004568, "PCB, fan power filter."
To install the fan power filter PCB -
- Disconnect the fixture from power.
- Disconnect 2-pole fan connector F2 and 4-pole fan connector 11 from the main PCB.
- Plug the fan power PCB into main PCB plugs 306, 303, and 304, with the components facing the center of the main PCB as shown.
- Connect fan connector F2 to the left 2 pins (PL2) of the fan power PCB.
- Connect fan connector 11 to the right 4 pins.
Note that the fan speed regulation feature works without the fan power filter but the noise reduction will not be as great.