The picture on my Sony DVD recorder/player sometimes flickers, and on one occasion when I was replaying a programme that I had recorded to the hard drive, the picture disappeared and I could only see AV1 in the top left-hand corner of the screen.
I however reversed the play to the beginning and started to replay the programme, and it replayed to the end with no further trouble.
Does anyone know if this is serious or just a matter of a loose connection?
You don't say how you've got it connected to the TV, but if it's by SCART lead, then it's almost certainly just a plug come loose. Check that the lead is fully inserted at both ends.