Got a lot of great ideas from these threads:
photos.google.com
I just purchased am ICX7450-32ZP. It's been my dream switch for many years, but I always knew it would be too loud. Others have outlines the pinout of the fan connector and how to trick the power supply into thinking that it has a stock fan, so I am going to post the differences in my mods. Firstly, I purchased a nonfunctional ICX7450-48 to gain an extra top cover (I did NOT want to use acrylic), power supply, fan, power supply blank, fan blank, and other miscellaneous parts. I purchased the necessary Molex fan connector for the fan housing and crimp pins for the connector. I also used this pulse generator and set it up on my oscilloscope for 50% duty cycle and 650Hz.

I immediately replaced the caps with high quality Nichicon. However, the fan mod sill failed at first because the pulse generator gets very finicky close to 50% duty cycle and as I approached 50% the waveform is lost completely. I thought I had it in a good spot, but it would run a while and then fail. Luckily, the 50% duty cycle widely believed to be "needed" by the Brocade switch to fool the fan sensor is not really exact. I increased the duty cycle to 70% and everything has been fine since.
In my mod I also retained the green/amber LED in the original fan board.
In my junk 7450 I removed the rails for the power supplies by drilling out the rivets. This allowed me to make a couple practice holes in the case on the back. I tried a new to me tool called a "nibbler" to cut the circle holes for the 140mm fans. I must say, where has this tool been all my life! And Amazon had it on sale for $20.
I also used the scrap case to screw the top back into when I made my real holes in the top cover. This did a perfect job holding the top steady and providing clearance for the nibbler tool (especially since the power supply rails had been removed earlier).
This was really a dry run and I plan to redo the whole mod. I'm going to replace the trimmers on the pulse generator with fixed value resistors, make a second Molex connector that is neater than the first one, and generally clean up the wiring. You can see that I just bunched up the fan wires near the fan control circuit and I'd like these to be short and to the point.
Here are photos:









I can just plug the fan box into the chassis with the pulse generator in it as you would an ordinary fan box. Only difference is the wire that runs from the pulse generator to the power supply fan plug, and the power wire that runs to the fans. I may actually pickup 12V someplace else on the final design.
Google Photos

I just purchased am ICX7450-32ZP. It's been my dream switch for many years, but I always knew it would be too loud. Others have outlines the pinout of the fan connector and how to trick the power supply into thinking that it has a stock fan, so I am going to post the differences in my mods. Firstly, I purchased a nonfunctional ICX7450-48 to gain an extra top cover (I did NOT want to use acrylic), power supply, fan, power supply blank, fan blank, and other miscellaneous parts. I purchased the necessary Molex fan connector for the fan housing and crimp pins for the connector. I also used this pulse generator and set it up on my oscilloscope for 50% duty cycle and 650Hz.

I immediately replaced the caps with high quality Nichicon. However, the fan mod sill failed at first because the pulse generator gets very finicky close to 50% duty cycle and as I approached 50% the waveform is lost completely. I thought I had it in a good spot, but it would run a while and then fail. Luckily, the 50% duty cycle widely believed to be "needed" by the Brocade switch to fool the fan sensor is not really exact. I increased the duty cycle to 70% and everything has been fine since.
In my mod I also retained the green/amber LED in the original fan board.
In my junk 7450 I removed the rails for the power supplies by drilling out the rivets. This allowed me to make a couple practice holes in the case on the back. I tried a new to me tool called a "nibbler" to cut the circle holes for the 140mm fans. I must say, where has this tool been all my life! And Amazon had it on sale for $20.
I also used the scrap case to screw the top back into when I made my real holes in the top cover. This did a perfect job holding the top steady and providing clearance for the nibbler tool (especially since the power supply rails had been removed earlier).
This was really a dry run and I plan to redo the whole mod. I'm going to replace the trimmers on the pulse generator with fixed value resistors, make a second Molex connector that is neater than the first one, and generally clean up the wiring. You can see that I just bunched up the fan wires near the fan control circuit and I'd like these to be short and to the point.
Here are photos:









I can just plug the fan box into the chassis with the pulse generator in it as you would an ordinary fan box. Only difference is the wire that runs from the pulse generator to the power supply fan plug, and the power wire that runs to the fans. I may actually pickup 12V someplace else on the final design.
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