HP 70001A Installation And Veri Cation Manual page 38

I/O This circuitry senses the readiness of the external HP-MSIB. If the indicator is
on, HP-MSIB communications are inhibited. The I/O fault indicator light will be
on if one of the following conditions is true.
The external HP-MSIB loop is not complete. Check that both ends of all
HP-MSIB cables are securely connected.
Not all the elements on the external HP-MSIB loop have the power
turned on. Verify that the power is on to all mainframes and stand-alone
instruments on the external HP-MSIB.
The mainframe is in need of repair.
HP-MSIB communication will resume as soon as the problem is corrected.
If an I/O light fault is indicated, the following steps will help isolate the
problem.
Disconnect both HP-MSIB cables from the mainframe at the mainframe
connectors. Is the I/O fault indicator still on?
NO
YES The HP 70001A Mainframe or one of the installed modules is probably
Note
It is possible that a module may disrupt all HP-MSIB communication with no
mainframe fault or no module error lamp turned on.
If more than one mainframe is used, or if other elements are connected to the HP-MSIB, all
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cables must be connected otherwise; the HP-MSIB will not operate. If a single mainframe
with no external elements is used, there should be no HP-MSIB cables connected to the
external HP-MSIB connectors of that mainframe, although a single cable looped from the
input connector to the output connector will allow the mainframe to operate.
5-4 Troubleshooting
The problem is either with the cables, or the element that was
connected to the mainframe with the cables.
Loop each cable \IN" to \OUT" to the mainframe HP-MSIB connectors.
If the I/O light comes on, that cable is faulty. If the light does not
come on for either cable, then the element connected with these
cables is faulty. Refer to the service manual for that element for
troubleshooting information.
faulty. Remove all the modules. Does the light still come on?
The mainframe is faulty. Refer to the HP 70001A Service
Yes
Manual for troubleshooting information.
No Replace the modules one at a time until a faulty module or slot
is located. Try the module in a di erent slot. If the problem
only occurs in one slot the mainframe or connector is faulty. If
the problem follows the module the module is faulty. Refer to
the faulty module service manual for repair instructions.
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