Occasionally when starting my HDR I just get a blank TV screen, apart from the message "!The receiver is not receiving a signal or the signal is too weak". Looking at the signal strength does indeed show signal strength of zero for all muxes. However the picture through the television tuner (the aerial signal is looped through the HDR) seems as good as normal. Everything is returned to normal just by using the remote control to re-start the HDR. What is causing it, and can it be cured?