Arista DCS-7048T-A Fan Modifications

ryan7

New Member
Nov 15, 2021
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I recently acquired an Arista DCS-7048T-A for free and it's a great switch, but it sounds like a jet engine, even during idle and on 30% fan override (with temps within 20c of the warning threshold).

I looked into replacing the fans with quieter models and came across this Reddit thread: https://www.reddit.com/r/homelab/comments/9tlhxi
Considering the PSU model (Emerson DS460S-3), I decided to swap out the OEM fan (SanAce 40) with the Noctua NF-A4x20 PWM, that was used in that post, before swapping the rest of the fans.
Following the documentation on the fan pin colour layout for the Noctua and OEM fan, I installed it, splicing the wiring together with K1 cable connectors to make that easier.

Closed up the PSU and reinstalled it. Upon turning it on the fan on the PSU will spin for a second or two, stop, spin again, then stop and then finally the switch will turn off completely.
I believe this may be related to the different RPM between the OEM fan and the Noctua, with the Noctua fan not being able to reach the RPM the PSU or switch is expecting.

Any idea why this might be occurring?

Thanks!