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2-2
PRIMARY TROUBLESHOOTING
PROCEDURES
Diagnostic Self-Test
Table 2-1 Error Codes
Troubleshooting
Begin troubleshooting by preparing the terminal properly and
running the power-on self-test and the diagnostic self-test.
The terminal diagnostic self-test starts in setup mode. This
procedure includes communications circuitry tests, memory
read/write tests, EPROM tests, and nonvolatile RAM tests. Two
special test connectors allow the diagnostic test to function. After
starting, the diagnostic test will run until you terminate it.
If
the
test detects an error, an error code and message display on the
screen. Error codes are defined in Table 2-1. See Figure 3-4 in
Section 3 for component locations on the terminal PCB.
Code
Failure Message
Location
0
Character RAM Chip
U3
1
Attribute RAM Chip
U9
2
Font RAM
U2
p
Code PROM Checksum
us
K
Setup Lost (Battery)
BATTI
d
AUXl Port 00, 01-ACK
Ull or Ul2
b
AUXl Port 02, 03-BUSY
Ull or U12
c
AUXl Port 04, 05-PE
Ull or U12
a
AUXl Port 06, 07-ERROR
Ull or U12
A
MAIN Port RTS-CTS
UIO or U7
c
MAIN Port OTR-OCO
UlO or U7
x
MAIN Port TxO-RxD
UIO or U7
Follow these steps to run the diagnostic self-test:
1 Tum off the terminal. Unplug it from its AC power source and
disconnect any communications cables.
2 Attach loopback diagnostic test connector LB 1 to the MAIN
port and the EVEN or ODD loopback diagnostic test
connector to the AUXl port on the terminal's rear panel.
Loopback connector pin numbers and signals for the ports are
shown in Table 2-2.
3 Plug in the terminal and turn it on. The test screen fills with a
"walking" RAM character pattern for about 90 seconds, then
the screen changes to a "walking" attribute pattern.
D
Note
To fully test the terminal, let the diagnostic self-test run
five minutes.
4
If
the test stops, the terminal beeps, and a letter or number
appears on the screen, refer to Table 2-1 for an interpretation
of the error codes before proceeding to the appropriate
troubleshooting flowchart.
5 After completing the test, turn the terminal off. Remove the
test connectors and reattach the communications cables.
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Table of Contents
Troubleshooting
