I have a Sharp 6 head video recorder, 5½ years old. No problems till a few days ago. When I playback what has recently been recorded, the picture disappears to a blue screen and comes back randomly, the speed indicator jumps between SP and LP, the sound is rubbish, and it's completely unwatchable. However, if I play it at double speed, the picture is OK (there is no sound, but it's not meant to play sound at double speed). Also the picture is watchable on fast forward. This happens on various tapes, and stuff that was recorded more than a week or so ago plays back fine. I have tried cleaning everything accessible (rollers and pinch wheels) with a Q-tip and meths, but it's made no difference. I know I should move on out of the Stone Age, but if you know a fix that will tide me over till we go digital, I'd be grateful for it.
I would suspect one or more of the drive belts to have stretched.
Time was when spares could be purchased from any reputable component seller – now due to the demise of the VHS format, you will be lucky to find that the manufacturer will stock the parts.
Inspection and replacement of the belts is easy, once you have removed the cover – you might be lucky and find Maplin sells a belt set which includes the size(s) you require.