Using a 633 to drive more than 4 fans


New member
I have a SuperMicro SC743 chassis which has a total of six fans (four on a midplane and two exhaust). I'm using my 633 to drive the four fans on the midplane, but the motherboard I'm using won't PWM the two exhaust fans. I'd like to use the 633 to control all the fans, if possible (and I realize that there's only four fan connectors on the 633). I'm open to any ideas.

Also, one of the fan connectors on the 633 won't PWM any fan attached to it...I'm starting to suspect that the 633 may be faulty. How can I RMA it?

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I don't have a 633, but I do have a SCAB hooked up to my 631. I control a total of 10 fans hooked to 4 points. Just use y-adapters. Also, make sure the 633 see only 1 RPM signal per chain (this will require 3-4 pins adapters to do).

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Write support(at)crystalfontz(dot)com (edit to '@' & '.') with your invoice number and request an RMA.

You could team up more than one fan per connector on the CFA-633 as long as you keep the maximum current within specification. Either only connect one tach, or disconnect both tachs and use the temperature monitoring to keep tabs on if they are working.