Need casemod advice for external fan (see pic)

[seligman]

I need to add an external fan to the cover of this Dell SX280.

As built there is no airflow over the RAM or HDD or Mobo. At times the HDD temp registers between 53 and 55° C which is way too hot. My plan is to install a 80mm or 120mm fan to the outside cover (see pic) and power it via external USB port, for easy removal.

Where should I mount the fan, and should it blow air in or out?

 

[amuffin]

Blow air in.

 

[stickg1]

Cut a hole in that plastic, about 3 5/8in. diameter for a 92mm fan. Get a fan, mark the screw holes, drill those out with a 3/16" drill bit. Mount the fan, purchase a filter to put over it to reduce dust intake. If its a tight fit inside the case then mount the fan so its on the outside of the case and you can still screw a filter on to the fan.

http://www.frozencpu.com/cat/l3/g47/c223/s547/list/p1/Fan_Accessories-Fan_Filters-92mm_Fan_Filters-Page1.html

You could do a 120mm fan too if you wanted.

 

[seligman]

Thanks.

I realized a potential problem with the idea of using a 92mm or 120mm fan. I was planning to wire up a 5-volt USB powered fan -- mounted on the outside -- for easy removal.

But I'm not sure I can get a fan that large powered off 5 volts. The Dell motherboard has no spare fan headers on the motherboard to be able to use 12 volts, and the power supply is external so I can't tap off the PSU like that.

Ideas to power the fan?

 

[seligman]

Instead of using a 5-volt fan, my latest idea is to tap off the 12-volt source where it enters the motherboard. Remember, these Dell SX280's are USFF design and the power supply is external.

Unless somebody has a better idea, I was thinking of soldering the fan wiring to the pins, but I don't know which pin is which.