I have a Sony VRD-MC1 that I have been using to transfer my home-recorded-from-antenna VHS collection. I need to clear out some storage space. The problem tapes were recorded in the late 1980s, off-the-air. The problem is not one of copy protection. It happens with only some of the tapes. Often the recorded material is in black-and- white. The tapes play fine for viewing on the TV. The recorder gives the message "check video cable". That is also the message if the VCR is turned off, for example. It appears that the signal from those tapes lacks something that the Sony requires. I tried using different VCRs to play the tapes to the recorder. I do know how the Sony acts when it detects a copy protection signal. It locks up and must be turned off to restart. This is not copy protection. I have found no way to transfer these tapes to DVD. Suggestions?