IBM 950, Руководство по установке и обслуживанию

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MAP 0310: Parallel Channel Problem Isolation
001
–
Note: This procedure requires a channel-trained IBM service representative or
customer’s channel-trained person.
– Make sure that all cables are marked so that they can be reconnected to the
appropriate adapters.
Table 3-3. Initial Symptom
Symptom Explanation Conditions That could Cause the Symptom
There is a communication problem
on a parallel channel. A symptom
indicates a channel communication
problem between the host and the
multiaccess enclosure. 1. Select/Bypass Switch set to B (bypass)
position (see Figure 3-19 on page 3-42)
2. Terminators have not been installed at the
end of the channel
3. Bus and tag terminators have been
interchanged (when you are using a
cabling scheme that uses the Channel
Interface-out)
4. Total bus or tag cable length is greater
than the maximum length of 113 m (370
feet). To calculate total cable length, take:
400 - (number-of-Parallel Channel
Adapters * 30 ft)
.
5. Total number of Parallel Channel Adapters
on this bus and tag cable exceeds the
maximum of six.
6. The Parallel Channel Adapter is cabled to
the wrong channel.
7. The logical connection is not defined
correctly (in the IOCDS)
8. Bent pins on the bus or tag cables or
terminators (which is often caused by
attempting to seat the connector without
using the attaching screw on the cable)
9. Defective:
a. Parallel Channel Adapter
b. V-cable
c. Channel Interface Cables
Run diagnostic tests (see “Testing the
Adapters” on page 5-49).
10. Host problem
3-16
3746-9X0: MAE Installation and Maintenance