Local Test - OKIDATA ML320 Turbo Service Manual

Page: 68
Service Guide ML320/321Turbo
Chapter C Software Diagnostics and Adjustments

3.3 Local Test

3.3.1 Circuit test mode
3.3.1.1 Setting
(1) Diagnostic test (set by menu)
(2) Test connector
Connect the test connector shown in Figure C-3-6 to the interface connector CN1 on the LXH1 board
3.3.1.2 Function
After the settings outlined in Section 3.3.1.1 are completed and power is turned on, the serial interface
checks the message buffer memory and interface driver/receiver circuit. It then prints characters.
To start and stop this test, push the SEL button on the front of the printer.
Details of this test are explained on the next page.
(1) The program revision using two numerical characters is printed.
(2) "LOOP TEST" is printed.
(3) Memory is checked for the message buffer.
(4) Prints "OK" is printed if the memory check is OK and "BAD" is printed if the memory check fails.
(5) Output level to DTR, RTS, and SSD signals is dropped low. If DSR, CTS, or CD signals is High,
"IF BAD" is printed. If DSR, CTS, and CD signals are all Low, "IF OK" is printed.
(6) Output level to DTR, RTS, and SSD signals is raised high. If DSR, CTS, or CD signals is Low, "IF
BAD" is printed. If DSR, CTS, and CD signals are all High, "IF OK" is printed.
(7) Transmits characters codes from 20H to 7FH is transmitted by SD signal. At the same time, characters
are received by the RD signal and stored in the message buffer.