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3Com 3870 3CR17451-91 - FAN not working too fast alarm

Frequent Advisor

3Com 3870 3CR17451-91 - FAN not working too fast alarm

Hi

 

We have some 3870 which are displaying a FAN fault.  All 4 Fan's are working but switch has a Fan alarm.  If you reset

swith it fails POST on all 4 FAN's: 

 

Fan Speed Test ...............
Fan 1 is not working - speed 09000 RPM -> too fast

Fan 2 is not working - speed 09180 RPM -> too fast

Fan 3 is not working - speed 09000 RPM -> too fast

Fan 4 is not working - speed 09180 RPM -> too fast
FAIL

 

I have replaced all 4 FAN's from another working unit but same FAIL.

 

Switch works fine.  Would it be power supply maybe?

 

Thanks

3 REPLIES
Trusted Contributor

Re: 3Com 3870 3CR17451-91 - FAN not working too fast alarm

Hi larry

 

Too fast fan speed are usually caused by overvoltage. Maybe because a damaed PSU or other electrical part.

 

br

Manuel

H3CSE, MASE Network Infrastructure [2011], Switzerland
Frequent Advisor

Re: 3Com 3870 3CR17451-91 - FAN not working too fast alarm

Hi Manuel

 

I have now replaced the PSU and still same alarm.

 

So it must be circuitry on main board.

 

Thanks

Occasional Visitor

Re: 3Com 3870 3CR17451-91 - FAN not working too fast alarm

Up to now my 3COM switches used to report alarms when a fan was not functioning. You would replace the faulty fan and proceed. Even with alarm ON, the switch continued to work.

 

But now with this 'new' alarm: all fans working too fast, the switch never passes POST!

 

HP offers no advice/solution. Any advice?

 

--- Performing Power-On Self Tests (POST) ---
UART Loopback Test ........... PASS
DRAM Test .................... PASS
Timer Test ................... PASS
PCI Device 1 Test ............ PASS
I2C Bus Initialization ....... PASS
Switch Int Loopback Test ..... PASS
Crossbar Int Loopback Test ... PASS
Fan Speed Test ...............
Fan 1 is not working - speed 10680 RPM -> too fast

Fan 2 is not working - speed 09960 RPM -> too fast

Fan 3 is not working - speed 10080 RPM -> too fast

Fan 4 is not working - speed 10140 RPM -> too fast
FAIL
------------------ DONE ---------------------