LG LA643x Owner's Manual page 59

• When the TV is turned on after inserting a CI Module, you may not have any
sound output. The Smart Card may not be compatible with the CI module.
• When using a CAM(Conditional Access Module), please make sure it meets
fully the requirements of either DVB-CI or CI plus.
• An abnormal process of CAM(Conditional Access Module) may cause a bad
picture.
• [Depending on model] If the TV does not display any video and audio when
CI+ CAM is connected, please contact to the Terrestrial/Cable/Satellite
Service Operator.