If the main display of the POSMac PM-K5500 POS Terminal does not function / only displays a blank screen, this may potentially be caused by a dead CMOS Battery. You may verify this by:

  1. Separate the device from a power plug for an extended amount of time (+10 Minutes).
  2. Restart the device and verify if the Time/Date previously set is retained or changed.


If the CMOS Battery has indeed died, it can be replaced by removing the Backplate behind the Unit main display, where it will be visible in the top center of the circuit board.


#1: Tap on "DELETE" whilst the Device is booting-up to launch the Device BIOS Configuration. In the BIOS Page, select the "Chipset" Tab, and click on "ENTER" when selecting the "North Bridge Configuration" option.


#2: In the "Chipset" page, configure the following options: 


LVDS/EDP Controller = Enabled

LVDS Panel Resolution Type Select = Single 8 1024x768


#3: Once the previous steps have been completed, navigate to the "Save & Exit" Tab, and select the "Save Changes and Reset" option to restart the Device with the configured BIOS options.


#4: Upon the device's restart, verify if the main display is functional.