Jumpy screen on PS1

[pusher]

Hi
When I start any game on my PS1, the initial bootup screen is jumpy as if the TV has lost vertical hold. This I'm not too bothered about because when the game starts, the picture is stable and the game works fine,
BUT
I've just burned a 'demo' version of Crash Bandicoot 3 and the game itself is still jumpy and doesn't settle down. I can see the game is working but it is obviously unplayable. Other games are still ok.
Does anyone know what the problem might be?
I used Fireburner to burn the bin file on Memorex 700 disks in a Liteon burner
Thanks for any help
Cheers
Pusher

[Jesta]

oops!! i just read it properly.

make sure all your connections are ok, if they are...hopefully someone will be able to help you.

i mis-read your original post! sorry!