Philips M3921A - Display;Audible Tones (All Monitors)

Troubleshooting Guide
Chapter 5 - Troubleshooting 57
Display/Audible Tones (All Monitors)
The following lists recommended actions to address problems with the
display and audible tones.
Condition Recommended Action
1. System powers-up
and…
• LCD screen is totally
black or white.
Or,
• LCD screen is
illuminated, but no
data is visible.
Or,
• LCD screen has data,
but is not illuminated.
Note: Pressing the A3 contrast adjust switch
causes the LCD contrast setting to
immediately change to normal, factory-
default value. Pressing the A3 contrast
adjust switch toggles the display between
the two different color schemes (black
background and white background).
1. A1 and A3: Adjust the LCD screen contrast by
pressing the CONTRAST button momentarily,
then turning the wheel four revolutions in each
direction. Turning the wheel clockwise should
brighten the screen; turning the wheel counter-
clockwise should darken the screen.
2. A3: Ensure red LED, located on the top left corner
of the Main PCB, is illuminated. If the LED is not
illuminated, the monitor is not in on state: follow
troubleshooting steps in “Power” on page 48.
3. Ensure that the backlight cable is connected to
the Main PCB.
4. Ensure that the LCD connector is properly
connected to the Main PCB and LCD PCB.
5. If problem persists, replace Main PCB.
6. A3: If problem persists, replace backlight PCB.
7. If problem persists, replace LCD assembly.
2. Monitor responds to
button press, but key
press tone fails to
sound.
1. Ensure that the speaker cable is connected to the
Main PCB.
2. If the problem persists, replace the speaker
assembly.
3. If the problem persists, replace the Main PCB.
3. Audible alarm does not
sound.
1. Verify alarm volume setting in the Alarm/Limits
menu, and test operation of the alarm tone by
pressing the volume button while the alarm
volume setting is displayed.
2. Ensure that the speaker cable is connected to the
Main PCB.
3. If the problem persists, replace the speaker
assembly.
4. If the problem persists, replace the Main PCB.