Fan noise

More recently, last few weeks, my HoloPort that has been running for several years without any real issues now runs its fan at a high speed from about 1100h AEDT to 1300h AEDT. The noise is so loud I am at a point where I am thinking the unit should be shut off permanently. Have logged into console but cannot find any setting to shut the fan down to a lower level. Any thoughts or advice would be appreciated.