Classic build issue for owners of Corsair Obsidian 650D case

[davemon50]

Short history: My case is Corsair Obsidian series 650D. It's a great case for mostly everything but it's been superceded by the 750D. On my recent build I just kept it and rebuilt with it. However, anyone who knows this case knows about one particular issue with it - the front case fan is a 200mm Corsair fan that is a 3-pin fan wired by default through the 3-speed controller in the front I/O panel. The controller is no longer available anywhere and it fails easily (I'm on my second one). The Corsair fan isn't the quietest either although it performs decently.

The other poor design feature (or perhaps this is actually intended by Corsair as built-in money grab) is that there's no space between the drive cages and the fan for any other replacement 200mm fans because it's too thin, only 20mm +/- a couple. So you can't for example buy a quiet Noctua 200mm or similar. At least not one that is 4-pin, see below.

Like others who own this case I wanted to sidestep the 3-speed controller and install a quieter 4-pin 200mm PWM fan that fits in that case location, but as it stands there are none. Zero. So I finally found and bought (and just today received from Amazon) the transformer board shown in the attached picture. It's a 4-pin PWM to 3-pin transformer rated for up to 1A, so basically controls the voltage for up to a few fans of the right size, off one of your MoBo PWM chassis fan headers. There's extremely limited documentation from the mfg. So I'm not sure of the quality of the signal. But in theory this should solve the issue.

I'll install it some time in the next day or so and report how it worked. If anyone has any cautions over this arrangement please let me know, but maybe it'll point some Corsair 650D owners into a direction that helps out.

[davemon50]

So just wanted to report that this transformer unit by Phobya works really well, and now I'm able to control the front 200mm fan in this Corsair 650D case via PWM control through the AI Suite 3 software. The controller is small enough that it actually fits very nicely nestled in behind the SupremeFX DAC mounted in that case slot. I attached a pic of it. It's a little hard to see in the pic because the back side of the DAC case is very reflective so it's hard to pick it out. Turned sideways it fits right on the tray without even sticking out. This turns out to be an elegant solution for this problem with this case.

On a side note, who in the world at ASUS thought that the CHASSIS_FAN3 header location was a good idea? It's in an impossible location, tight on all 4 sides between the RAM (I have 2 of those 4 slots filled on that side), the back fan (where I have a double width radiator/fan combo, just on top of PCIe slot 1, and just in front of the rear I/O panel. Seems really stupid to have it there, and I had to remove my cooling unit just to have a chance at seating the wire on the header. Almost had to remove the video card too, but using pliers I was able to finally get it seated.