IBM 8237, Installation And User Manual

Page: 92 / 166

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Copyright IBM Corp. 1997
4-1
Chapter 4. Troubleshooting, Installation, and Replacement
Procedures
This chapter provides diagnostic techniques and replacement procedures for the
IBM 8237 Stackable Ethernet Hub 10BASE-T, including a parts catalog.
Problem Determination
There are three methods of problem determination for the 8237:
1. Observe the LEDs. See "LED Symptom and Fix Listing" for a list of symptoms
and fixes.
2. Swap hubs within the stack. See "Hot-Swapping 8237s" on page 4-3 for a
description of how to hot-swap an 8237 in the stack.
3. Observe the results of the diagnostic power-on self-test (POST) by connecting a
terminal to the management port. See "Problem Determination through the
Management Port" on page 4-3 for more information.
LED Symptom and Fix Listing
Table 4-1 (Page 1 of 2). LED Symptom/Fix Table
SYMPTOM FIX
During POST, one or more LEDs remain ON
during the test. If a failure is detected, the
LEDs remain ON and the Hub ID display
shows “F.” The normal power-on activity is for the
Link/Activity, Partition, and Utilization LEDs
to blink ON/OFF for 4 seconds; all other
LEDs remain ON during this time and the
Hub ID display will show “18.” Then as each
test is performed, the five Collision LEDs will
turn ON in sequence, from the first to the
last, and the Hub ID display will show “P.”
While these tests are in progress the
Backplane LEDs continuously blink ON/OFF
in sequence. After the tests, if any of the
Collision LEDs remain ON and the Hub ID
display shows “F,” replace the 8237.
Two hubs in a managed stack display the
same ID number. The physical stack is logically divided into
more than one stack, with each having one
or more management hubs. Check for loose
or disconnected Stack Link cables.
Note: In an unmanaged stack, the ID
numbers of the hubs in the stack are not
significant.
A hub displays no ID number, or the hub
displays no meaningful ID number. Meaningful numbers are 1–10. Verify that
the hub has power. The Power LED should
be ON. If no problem is found, replace the
failing hub. If there is no change, replace
the primary management hub in the stack.
The primary management hub displays the
Prim LED ON.