Problem with LSIS MASTER-K200S

[artklim]

Hello, we operate a machine on which the MASTER-K200S CPU K3P-07AS is installed. When replacing the battery, the lower switch TEST MODE was accidentally switched to the ON position. After that, the controller stopped showing any indication and it became impossible to connect it to the PC. What happens to the controller when the bottom switch is turned on and can we return it to its previous working state ourselves?