[SOLVED] PSU wont turn on after fan replacement.

Mar 18, 2020
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I acquired an older Super Mirco Server. I replaced the system fans with Noctua 40x20 fans to try to quiet the damn thing down. The Noctua's worked great on the system. The last loud fans was inside the PSU. I again swapped it out with 2 Noctua 40X20 fans but when i power the server on all it will do is pulse on and off. If i reconnect one of the original PSU fans back to the PSU fans headed everything work fine. Any ideas as to why the PSU wont turn on unless it has the original counter rotating fans connected??

The PSU is a "PWS-561-1H20"
 
Solution
Servers are not ment to be quiet. Just an FYI.

Make sure you didn't wire the new fan incorrectly (backward).

My thoughts are the PSU senses the new fan differently than the old one (they have different power draw or something) , so it thinks the fan has failed and powers off to prevent damage.
Servers are not ment to be quiet. Just an FYI.

Make sure you didn't wire the new fan incorrectly (backward).

My thoughts are the PSU senses the new fan differently than the old one (they have different power draw or something) , so it thinks the fan has failed and powers off to prevent damage.
 
Solution
Mar 18, 2020
2
0
10
I work in a server room so I completely understand that servers are not quiet. Especially 1ru servers. This was just a “see if I could do it” project. The sever was free.

The original PSU fan is 12v and .72A. Just a bit more then the Noctua. Ha ha ha ha. So I think you are 100% correct about the PSU thinking the fans are dead and it is going into some kind of protect mode.