I purchased an amcrest DVR security camera system but was disappointed by how loud the fan was for it. Since I was going to keep the DVR in the same room that I slept in something needed to happen.
Swapping in a new fan is very easy, all you need is a phillips screwdriver and a new quiet 40mm PC case fan.
Step 1: Remove the Fan
Remove the lid to the DVR, there are two screws on the side and 4 on the back. Make sure its powered off and all cables are removed first. Don't be scared, its simple and you wont hurt anything.
As you can see in the pics, the fan is held in with two screws and has a pretty standard 2 pin connector.
Remove the two screws holding the fan in and then remove the wire connector to the main board. Note where you removed the connector from.
Step 2: Replace the Fan.
This is the fan I used, there are a few other ones out there that will work but I have used this brand before and it fit perfectly.
Link to the fan: http://www.amazon.com/gp/product/B009NQLT0M
The fan came with new screws and a 3 pin to 2 pin adapter which I used for the install. Once everything is in, power up the DVR with the lid off to make sure the fan is working and moving air. Then power it down and screw the lid back on.
Congrats, your DVR is now a lot quieter.