# Dell C521 Case Swap



## Tank252ca (Apr 24, 2007)

Q: Is it possible to change the case of a Dell C521 to allow for full height add-on cards?

A: Yes, it's possible, but not recommended.

That's the short answer, so here's the long version. My neighbour wanted to upgrade the video on his Dell C521, and purchased a full height video card not knowing that the C521 only fits half height cards. The preferred method would have been to purchase a Sapphire X1600 Pro HDMI which is about the fastest half height card at the moment. Since he was stuck with his new card I recommended a new case. The caveat is that the C521 is a micro BTX motherboard so you are limited to strictly BTX cases.

The case I recommended was the Antec BK640B viewable here: http://www.antec.com/ec/productDetails.php?ProdID=01640
The case is silver and black and the front grill is lit up with a blue led and looks pretty nice for a reasonably priced BTX case. The power supply is only 380W, which is more than the stock C521 power supply, but keep that in mind when upgrading your system. It's enough for a mid-range video card, but don't expect to add extra drives, memory and high end video to this supply. You'd be better off starting from scratch with a new build.

Disassembling the Dell was not too difficult, but there are several aspects about their design that makes this case swap far from perfect. If you're unwilling or unable to do some custom work, don't bother reading on. Sell your Dell and upgrade to a new system. If you're hell bent on changing cases, here are the hurdles to overcome.

The C521 motherboard has one less mounting hole than a standard micro BTX motherboard. I had to break off one of the stand offs from the case to mount the C521 properly (lower front corner of the case, second of two stand offs).
The CPU fan was in a special enclosure that will not transfer to a new case. I had to custom mount the fan to the fan shroud on the front of the case with sheet metal screws and washers. While this worked fine for cooling, the shroud is plastic and causes some vibration so the replacement case ends up being a little noisier than the original Dell case.
The Dell case uses plastic hard drive and DVD-ROM mounting brackets for noise isolation, while the Antec case uses metal drive cages, so again, the Antec case adds a little noise here. I had to mount the hard drive below the DVD-ROM because the Dell cables are too short to locate the hard drive in the lower drive cage. The Dell cables are barely long enough for the new case, so route the cables in a straight line to the motherboard connectors, or grab some longer SATA data cables.
Any other add-on cards on the Dell will be half height and won't fit into a full height case. If you need to keep the other cards like a TV tuner or modem, a new full height mounting bezel will need to be fashioned. I had to take a blank bezel (used to cover the openings when no cards are installed) and drill it out to match the one on the TV tuner card. A drill press is recommended to accurately locate the holes. I still had to hand file the hole for the SVHS connector for proper clearance. We decided to forgo the modem since he had high speed internet and didn't use the modem card.
Most motherboards include an escutcheon plate at the back to cover up the PS2/USB/ethernet ports. On the Dell this is built into the case itself, so there is no plate to transfer to a new case. I had to carefully peel off the label on the back of the case and glue it to the RF shielding around the ports to cover up the rectangular hole at the back to the case. This label only covers 90% of the hole leaving a small gap around the outside edge.
Most importantly, the Dell front panel connector module contains diagnostic circuitry and uses a nonstandard connector on the motherboard. This means that you can't simply unplug the old front panel jacks and plug in the new ones. The original module needs to be plugged in, so I fastened its mounting bracket to the back of the case (plenty of room now fortunately). There is a second USB jack on the motherboard, so I was able to plug the front panel USB jacks into the motherboard and they work fine. The real difficulty comes with the power switch and headphone/mic jacks.
I soldered a pair of wires to the old front panel circuit board onto the two pins of the old power switch. I initially tried to connect the wires to the new power switch, but it just would not work. Most likely the new power switch has an LED built in which interferes with the Dell diagnostic circuitry, so I was forced to connect the wires to the new reset switch instead. This worked fine for power on/off and the old Dell had no reset switch any way. The blue front panel LED on the Antec case made for a fine power on indicator.
The bigger problem was the headphone/mic jacks. It would have taken a great deal of time to trace all of the connections and figure out how to wire the new jacks into the Dell front panel diagnostic board, but my neighbour doesn't use headphones so we left the front panel jacks disconnected. A quicker method might be to fashion a bracket and face the old jacks out the back of the case, but either way, making the headphone jack available in a new case is the worst part of this case swap.

If the headphone/mic jacks are a must, I strongly recommend against this case swap. For all of the hours involved in trying to get the jacks to work along with the above noted extra labour, you would be better off purchasing a new ATX motherboard (and CPU cooler), which would then give you full choice in a new ATX case, as there are very few BTX cases to choose from at the moment, and Dell computers are not designed to be upgradeable in the first place.


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## kiwiguy (Aug 17, 2003)

And if you bought a new notherboard, then you would need a new version of Windows (as the Dell is BIOS locked to the Dell Motherboard), probably new RAM, Video, PSU, ... in other words a new PC.

Brand name PC's are not really upgradeable as you note. Mainly (in terms of non-case or HDD/RAM) as that just increases the calls to the makers service center, so by limiting what you can do it saves that traffic and (ironically) means the stock system is actually very reliable and stable, since you really can't "fiddle".


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