PSU Fans fast and loud

Brian
Brian used Ask the Experts™
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I'm a technician at a school department and we recently replaced 30 PCs in a lab w/ refurb Dell 780s.  Four out of the 30 have PSU fans that rev full speed and stay there until shutdown.  The four are on the same table, side by side, and I thought that to be to much of a coincidence.  Thinking maybe it was a power issue,  I tried moving one to a known good location in the room, but it still fired up like a jet engine, so I guess it was just luck that the 4 that had the same issue ended up side by side.  Before I send them back, I'm looking to see if anyone has any insight into the issue.  There is no change in fan speed at all while the machine is running, it's full throttle all day.
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In the BIOS (F2 at power on), there is a setting under Power Management called Fan Control Override.  If this is set to "enabled" then the fans will run at full speed.
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
Also (I have had this issue with IBM boxes), upgrade the BIOS if you can. That, in addition to the good suggestion above should solve your problem.
"Four out of the 30 have PSU fans that rev full speed "
BIOS settings should correct his otherwise send them back for replacement.

If you need to see the manual:
ftp://ftp.dell.com/Manuals/all-products/esuprt_desktop/esuprt_optiplex_desktop/optiplex-780_Service%20Manual_en-us.pdf
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Have you checked to see if those 4 have the same PSU's as the others?
Being refurbished could have included replacing the power supplies in some of them.

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Commented:
Thanks for the responses!  Power Management in BIOS was the solution.  I never knew fan speed to be an option.  Now, seeing as how all four PCs with the PSU issue were on the same student table, it looks like my next task is a BIOS password...Thanks again.

Also, I'm new to EE and I'm not sure how the points work  Should I have awarded all to the first expert who answered with the right solution or split them up between correct solutions like I did?
Spitting points is entirely your option, when, and if another soution helped to solve or added further infomation to back up the solution.

Thank you for your closing comment.

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