The first two steps are to make sure that the paths AC power supply and battery to +5V
System Board supply voltages work correctly.
What To Do if the Monitor Cannot Be Switched On, AC powered
• Remove the battery.
• Connect AC power. The AC Power LED should switch on within several seconds.
• Switch the Instrument on. The On-Off/Standby LED should switch on.
• If either the AC Power LED or the On-Off/Standby LED remain off, check if the Monitor
Bezel and display cables are connected properly to the System Board.
• Check the display cable is seated correctly (particularly if it is offset by one row too low–in
this case the +5V is shorted to ground and the Instrument remains off).
• If the AC power LED still remains off, check the AC power supply. (If necessary, replace
the fuses on the Power Supply board or replace the complete Power Supply).
• If the AC power LED still remains off and/or the Monitor still cannot be switched on, the
Monitor Bezel might be defective. Try a known-good Monitor Bezel.
• If the AC Power LED still remains off and/or the Monitor still cannot be switched on,
replace the System Board.
What To Do if the Monitor Cannot Be Switched On, Battery powered
• Connect AC power to the Monitor and make sure it can be switched on and operates prop-
• Make sure that the battery is adequately charged (press charge indicator on battery, at least
one green LED should switch on).
• Insert the battery into the Monitor (AC power still connected), the Battery LED should
switch on (green, yellow, or red).
• If the Battery LED remains off or is red, replace the battery with a known-good one.
• If the Battery LED still remains off, either the LED is defective or the battery control circuit
on the System Board is defective.
• To check whether the Battery LED is defective, disconnect AC power and switch on the
Monitor. If the Monitor works, most likely the Battery LED is defective. In this case,
replace the Monitor Bezel.
• To check whether the System Board is defective, disconnect AC power and switch on the
Monitor. If the Monitor remains off, either the battery fuse (surface mounted) on the Con-
nector Board is blown or the System Board is defective. If necessary, replace the Connector
• If the Monitor still remains off, the battery control circuit on the System Board is defective.
(Replace the System Board).
Initial Instrument Boot Phase
The following steps are to ensure that the Monitor finishes its first boot phase and the
application software starts running. The application software is running when the yellow
LED blinks slowly (1 time per second).
For these steps it is assumed that the Monitor is powered correctly and the +5V System Board
supply voltage is okay. This is indicated by the On-Off/Standby LED and the green LED on
the Main Board (upper left) both on.
Troubleshooting the Instrument
Part 1 Troubleshooting Checklists