I have a curious problem with a Toshiba RD-XV48DTKB HDD & DVD/VCR:

HDD and DVD recordings play perfectly, but all VCR recordings are unwatchable because of the image distortion; it looks like a very unstable double image as if the synchronisation signal was inadequate, however the sound is OK. I decided to record the image distortion onto a DVD to transfer to my computer and send a video clip to one of the video problem forums to help solve the problem. However, IMMEDIATELY I pressed the VCR-DVD dubbing button, the image corrected itself and I can use the VCR facility without any problem - I use a re-writeable DVD and then wipe it when full. The same improvement occurs when dubbing to the HDD.

I originally thought this must be a mechanical problem but given the fact that the problem goes away when dubbing is started,an electronic cause seems more likely? - Any help would be greatly appreciated.