HP 3000 Series Installation And Service Manual page 51

Maintenance
5-14. HP Support Troubleshooting Procedures
More extensive troubleshooting can be done by the HP Customer
Engineer by using the support-user interactive dialogue of DSM.
When support-user diagnostic testing of the INP identifies a mal-
function within the INP PCA boards, field repair of the boards is
limited to the replacement of the Random Access Memory (RAM)
chips. Any other malfunction must be remedied on an exchange
basis. (See paragraph 5-2, "Repair Philosophy".)
When the HP Customer Engineer arrives at the computer site, the
recommended troubleshooting sequence is as follows:
a. Determine that the INP is not currently in use.
b. Before initiating any other action, open the computer card
cage door and observe the INP self-test LEDs (see figure 5-1
for the location of the LEDs). Note whether the LEDs are
flickering or a static pattern is being displayed, and make a
written record of which LEDs are lighted. This information
may be needed later if the problem persists beyond the
initial steps of troubleshooting.
c. Disconnect the modem cable (or the direct-connect cable) from
the edge connector of the INP PCA board to physically isolate
the INP subsystem for testing.
d. Press the manual RESTART switch (figure 5-1) to initiate the
self test.
e.
Observe the INP self-test LEDs.
interpretation of the meaning
patterns.}
(Refer to table
of the various
5-1 for
LED light
f. If LED 3 is lighted in combination with any of the other
LEDs, a RAM data chip failure is indicated. To determine
which RAM chip is defective, note the light pattern being
displayed by LEDs 7 through 4 and compare this pattern with
the information shown in table 5-2. (If LED 3 is not
lighted, skip steps g through h and go directly to step i .}
5-8