Teledyne API Model 100AH SO2 Analyzer Instruction Manual, 02417, Rev. D
10.3 Electronic Subsystem Troubleshooting and Adjustments

10.3.1 Computer, Display, Keyboard

The purpose of this section is to determine if the computer subsystem electronics hardware are
working properly. Assessment will make it the board level.
10.3.1.1 Front Panel Display
The front panel display is a 2 line by 40 character display. It has its own microprocessor to
decode commands and display characters. It contains a self test feature. To test the display:
1. Turn off the power to the instrument.
2. Fold down the M100AH front panel.
3. Disconnect the 24 line flat ribbon cable (J2) that connects the computer parallel port to the
keyboard.
4. Turn on the M100AH power switch.
5. Observe the front panel display. If the display successfully completes its power on self test, it
will display a single underline character "_" in the left most character of the top line of the
display. If this character is present, the display is working properly.
6. Turn off the power to the analyzer, and re-attach the 24 line cable to J2, and proceed to the
next test.
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