Today on the bench, a Yamaha Stagepas 300 with very noisy fans. Over time, dust will build up inside the unit and bind up the fan bearing causing a grinding and whirring noise.
I chose a sleeve bearing, low noise computer fan set for this application. I did have splice the old connector on to the new fan since Yamaha used a smaller connector than standard.
There are two fans. 50mm and 40mm
The 50mm one is sitting out in the open, two screws and its out! Replacing this one is simple.
The 40mm one is buried and required all of the lower board screws to be removed and pulled from the casing.
I also needed to countersink the fan mounting holes in order to mount the fan correctly.
Reassemble and test. Nice and quiet! No fan noise.