Philips M3001A Service Manual page 190

Part 1 Troubleshooting Checklists
What Happens During a Regular Boot, AC powered, without Battery
The Monitor Bezel LEDs, tone and display come up as follows:
• The AC Power LED is on.
• When the On-Off/Standby switch is pressed, the On-Off/Standby LED switches on imme-
diately.
• The Alarm LED and the Suspend LED both switch on red and the Battery LED switches on
yellow. After 1 second, the Alarm LED switches to yellow, after 1 second all three switch
off.
• At the same time as the LEDs switch off, the speaker is tested with an audible tone.
• Shortly after the LEDs switch off, the display backlight switches on and the M3/M4 logo
displays.
The Three LEDs on the System Board come up as follows:
• Green LED—When the On-Off/Standby switches pressed, the green LED switches on
immediately.
• Yellow LED—The yellow LED blinks 2 times per second after the red Error LED switches
off then slows down to blink 1 time per second when the first system boot phase finishes
(after approximately 2 seconds).
• Red LED—The red LED switches on for about 1 second after a power on (RESET) of the
System Board then switches off.
If the boot process is not successful for any reason, check for obvious problems (Part 1
Troubleshooting Checklists).
What To do If the Display Remains Dark
If the three LEDs on the System Board indicate that the first boot phase has finished
(green=on, red=off, yellow=blinking once per second) but the display remains dark, check
the following:
• Check that the display cable is seated correctly.
• Check (in the Display Assembly) that the video flex layer is snapped correctly onto the con-
nectors on the Display Adapter Board and check the TFT panel by pressing onto the flex
layer at the connectors.
NOTE Do not try to remove the video flex layer because, if snapped on correctly, removing it can
easily damage the SMT solder joints.
• Check that the cables of the backlight tubes are seated correctly into the backlight inverter.
• Check the backlight tubes are working correctly (broken, damaged, or worn).
• If the display still remains dark either the Display Assembly or the System Board is defec-
tive. It is recommended to replace the Display Assembly first.
174 Troubleshooting the Instrument