Conference netcad::hub_mgnt

    
    I don't have the correct figures in front of me right now, but I'll
    forward this to someone who does...
    
    This _could_ be a result of improper mounting of the hub causeing a bad
    connection on the lower connector.  The 5V power requirement for MAX
    modules is read using pins on that connector, and a poor connection can
    cause them to be read incorrectly.  Make sure that if rack mounted, the
    hub is attached to the side panel with _all_ the supplied screws; if
    wall mounted, make sure that the little spacer feet are attached to the
    hub on the holes near the seam between the top and bottom sections
    (_not_ the bottom corners).
    
    Also check the pins on the lower connector on the Max modules; look for
    any that are bent or pushed in.
    
    I suggest the following proceedure:
    
      Make sure you have MAM firmware V3.0.0 (it provides better 
         debugging information for this)
    
      Remove all modules and all but one power supply.
    
      Put the console into Event Display mode (menu choice 12)
    
      Insert remaining power supplies one at a time, waiting between
         each to see the messages on the Event Log; it should indicate
         a good status for each.  Also double check the LEDs on the 
         supply, and the power display on the hub LCD.  It takes about 9 
         seconds for the hub to recognize each new supply; be patient.  
    
      Insert each module one at a time, starting with the 90 modules.
         Check that the power display decrements correctly for each.
    

    
   > I don't have the correct figures in front of me right now, but I'll
   > forward this to someone who does...
    
    Thanks, I kept getting conflicting information from different locations 
    about the power consumption, so I ended up taking our own hub to bits 
    and plugged each module in one at a time to see the power requirements 
    (I didn't have some of the modules so I used the documentation for the 
    figures)
    
   >This _could_ be a result of improper mounting of the hub causeing a bad
   >connection on the lower connector. 

    The customer has two hubs and both are exhibiting the same symptoms. 
    According to the customer he noticed the problem when he connected the 
    comms cable to the brouter. Removing the cable didn't clear the problem.    

   >Also check the pins on the lower connector on the Max modules; look for
   >any that are bent or pushed in.

    I'll get the customer to check.
    
   >I suggest the following proceedure:
    
   >   Make sure you have MAM firmware V3.0.0 (it provides better 
   >      debugging information for this)

   Customer is running V3.0.0
    
   >   Remove all modules and all but one power supply.....
    
   >   Put the console into Event Display mode (menu choice 12)
   > for each....

   This will have to be done out of hours as this is a live hub. I'll let 
   you know how I get on.

   Thanks for the help so far,

   POL.    

    
    A quick update...
    
    The customer repowered the hub without removing any modules and
    everything came back up again and stayed up. For the record after
    powering up he still had 53.8A at 5V, 8A at 15V and 239W left on the
    MAM module display. Which as suspected, wasn't even getting close to
    using the available power from the third PSU.
    
    We're just putting it down to a one off at the moment but he'll keep an
    eye on the situation and inform me if it re-occurs

    Scott's reply, .1, is right.  You are most likely seeing a pin-wipe
    problem on the bottom connector.  We are currently working on
    a ECO and possible FCO to fix this.  We should have specific
    recommendations late next week.
    
    The fault scenario goes like this:
    
    A single module in a hub appears to work okay.  As the hub becomes
    populated, the middle slots are succeptible to inadeqaute pin wipe
    causing incorrect power values being read.  If the corrupted value
    is an 0xE (a reserved value), the MAM processes the request as
    a need for 99 Amps or 495W.  The Hub power system is capable of
    420W, thus a request for 495W will result in all modules to the
    left of the inserting module to power down.  
    
    A temporary 'fix' is to whacked the bezel at bottom of the offending 
    module with the butt of a closed fist.  This typically causes enough
    force to provide some pin wipe.  We realize that this is unacceptable,
    and are working on a mechanical fix.
    
    My apolgoies for the inconvenience,
    Mike S.  
                                   

    
    Since you announced to give some recommentations late next week, 
    (1-jul-94), I wanted to ask for them.
    
    I have a customer, who might have experienced that power problem.
    2 of his Decserver900 were totally dead, not even the power LED
    was burning. Could this have happened due to the scenario described in
    the previous note?
    
    After having them plugged out and in again, both were running fine.
    He has 4 power supplies in his HUB.
    
    thanks eva

    Hi,

    I have been installing a number of DEChub 900's for a customer and about 
    3 out of the 5 are showing symptoms similar to that mentioned in .0. The
    configurations are based around 1 power supply, a DECrepeater 900 (32
    UTP ports) and 1, 2 or 3 DECbrouter 90's. I still have 6-7 sites to go
    and I am worried about this problem.

    If I type reload at the console prompt of the DECbrouter, when the
    brouter software has reloaded and its interfaces are re-initialising the
    DECrepeater 900 looses power and only gets it back if I power cycle the
    whole hub.

    Any more information available to fix the problem?

    Cheers
    Neil