Okay I have a howling fan.
So I figure time to replace it.
I have torn the unit down for a cpu upgrade,but I can't find how to take the side and back panels off to get to the fan.
I guess I will figure it out when I attempt this.

Then my next issue is a replacement fan part number.
Does anyone have one?
I would like to have one in hand when I do this.

_________________
VGA/PS2 Keyboard/PS2 Mouse/Serial debug board
Popcorn C-200
Popcorn A-200
Dune HD Connect
Rasberry PI OSMC(KODI)
ReadyNAS RN316
Amazon FireStick
Amazon ECHO
AnyDvD
MyMovies

Taking the side panels off won't help much, they're just plastic covers over the metal cage. Taking off the rear may be helpful. A search will turn up numerous discussions, such as these:
viewtopic.php?f=25&t=10429
viewtopic.php?f=2&t=12545

_________________
Alex Kuretz
Remote Notification: Monitoring and alerting for your Home Server via email, Twitter, text message, RSS, push notifications, and on your Mac desktop
Have you tried our Add-Ins?

I believe to get the back panel off easily you need to remove the side panels but in doing do one has to be careful not to break the locking tabs on the side panels. To be honest the fans just slide out in opposite directions from each other they are silicone mounts and with the backplane removed they are fairly easy to get at unless you have large hands.

Thing about the side panels is I have received units for repair where the side panels just fall off and I did have one where someone broke the top locking clip and attempted to glue it back on.

_________________
Exploring the possibilities!

Migrated from WHS2011 to WS2012E: HIGHLANDER

~ Norco 4220 Enclosure
~ Gigabyte GA-990FXA-UD5
~ AMD Phenom II X4 995 3.2 GHz
~ 8 GB Corsair Vengeance DDR3 1600 (PC3 12800)
~ 3 Supermicro AOC-SASLP-MV8

Thanks guys.
I thought it would be easier if the back cover was off and I had read somewhere the sides have to come off first to do so.
I will probably figure it out once I break it down again.
So now to replacement fans.
I will be adding a 4gb ram stick and while I have it apart I wanted to replace both fans since one is howling pretty bad,but it could be both.
Anyway I have never seen a true replacement fan anywhere.
At least not for a ex490 listed.
The referenced links take me to models prior to the ex490. So I am not certain they are the same for the fan parts.
Someplace on the internet I found a post a while back that somebody could not find a 4 wire fan so used a 3 wire fan?
I can't seem to find it again. I don't believe it was at this site.

_________________
VGA/PS2 Keyboard/PS2 Mouse/Serial debug board
Popcorn C-200
Popcorn A-200
Dune HD Connect
Rasberry PI OSMC(KODI)
ReadyNAS RN316
Amazon FireStick
Amazon ECHO
AnyDvD
MyMovies

The fans are PWM or Pulse Width Modulation type fans. These can be found from a wide range of venders. You would need to pay close attention to the CFM & Noise Rating to achieve the proper air flow to noise level ratio. I know the stock fan specs have been posted in the forums by myself along with fan pics and part numbers but that was a long time ago.

I have fans I can pull out of other units that I could make available to you if you do not want to go through all the hassle of figuring out which fans to use to replace the fans your having issues with but I feel you might be better off looking for a more efficient fan from a supplier. Thing about fans is they are inexpensive and yet so vital to the continued operation of your server.

_________________
Exploring the possibilities!

Migrated from WHS2011 to WS2012E: HIGHLANDER

~ Norco 4220 Enclosure
~ Gigabyte GA-990FXA-UD5
~ AMD Phenom II X4 995 3.2 GHz
~ 8 GB Corsair Vengeance DDR3 1600 (PC3 12800)
~ 3 Supermicro AOC-SASLP-MV8