Maintenance
37
7.3.2.7
Replace the DU back into its mounting.
Step 1. Replace the Display Unit back into its mounting by installing the four 10-
32 Phillips head screws. Install the Display Unit pigtail back into its original
socket.
7.3.2.8
Run Test Mode and verify correct keypad operation.
Step 1. After the Display Unit has been powered up and configured, put the
Display Unit into Test Mode by performing the Test Mode key sequence. Press
and hold the “event acknowledge” key and simultaneously press and then
release the “select” key. Release the “event acknowledge” key and notice that
the Display Unit is now in Test Mode. Test the keypad by pressing any single
key, the corresponding key symbol on the LCD display will turn black.
Subsequent key presses will toggle the LCD key symbol between black and
white. Back-lighted LCD modules will toggle the back-light on and off when the
Contrast key is pressed multiple times. Verify that all keypad keys are functional.
Repeat the Test Mode key sequence to exit Test Mode. Discard the old
EPROMs after you have verified proper Display Unit functionality.
The Display Unit version number is displayed in the upper left hand corner of the
LCD module in test mode.
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