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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

3115.0. "Power supplies going off line?" by MPOS02::THOMPSONM () Wed Jan 03 1996 18:25

    I have a customer with 11 DEChub 900's.  Over the last few months
    a number of power supplies have gone dead and need to be de/reinserted 
    to come back to life.  A couple did not come back.  Is there a known
    problem with the H7890-MA, HW Rev.B-03, power supply that would explain
    this?  These hubs need to be up all of the time and all have N+1 power
    and are on UPS's.  Any additional thoughts?  Help is appreciated.
    
    -Mark
T.RTitleUserPersonal
Name		DateLines
3115.1Check Temperature where hub is locatedNETCAD::B_MACARTHURWed Jan 17 1996 11:5518
    Mark,
    
       The only time the supply can shut off and not re-start is if an
    overvoltage or overtemperature condition is present in the supply.
    Other cases such as a temporary short or overcurrent will cause the
    supply to hiccup and restart. When it latches off it's due to a very
    high temperature problem or the 5V output on the supply rising above
    6V. The temperature problem could be due to blocked airflow or the
    hub being in a very warm closet. The overvoltage problem can only 
    occur when something fails in the supply. This would not recover when
    you power cycle the supply ( it would shut itself down immediately
    on the re-application of AC power ). I'd check the temperature of the
    location where the hub resides. If it's within limits, let me know.
    I haven't seen any problems like this before.
    
    Regards,
            Bob