I like the PC fans I use them in a Neve Genesys that runs too hot.
A window screen will not allow the proper circulation if it is completely open. Rather than suck air from the bottom of the rack the fans will also pull it from around their frames.
I always replaced like with like as best as possible looking for a high spec for hours of operation. Pabst, ComairRotron and now NMB ball bearing style are working over 10 years constant use in a 68 degree machine room before going dry.
If I were to improve the SSL design I like the isolated original panel idea the best. Perhaps weatherstripping around the top of the rack and just sit the panel on top of that. I never measured the SPL of the panel freestanding vs mounted. You have 8 or so other fans in a 4048 rack anyway. It's supposed to make noise, thats how you know the power is on.
A word on contact cleaning- the cleaning is only half of the job. The contacts on switches and connectors should be conditioned after that. Especially switches. They come from the factory with lube on the contacts and actuator. Cleaning an old switch with whatever removes the lube with the crunchy sounds. You want to replace that to keep the switch working smoothly. Same with edge contacts. I think of it in terms of chemistry. If you leave contacts dry then the environment will determine what to put around the contact surfaces. If you use a conditioner YOU control the connection. ProGold, Electrolube, Renu, etc used miserly are good practice.
Mike
