flex pendant not resoponse

BasselAlmouie

hello,
i have robot irb 4600 with controller IRC5 M2004,
when i switch on the controller the flex pendant show the test of ram and self testing of the main computer,
then pass to searching for the robot controller system,
first found the panel board then the drive controller then the status led become green continues.
then the flex pendant stop at this stage and not response to any things.
i check the events log from the robotic studio there is 2 hardware event the SMB battery lost and revolution counter not update.
could you please help me to know if the SMB battery cause this problem, and what i must do to fix this problem?
thank you in advance