Sound but no picture, picture returns after switch off/on.

It can be a temperature related problem, where a component is working on the edge of spec. When powering the set down, and up again, the specs are changing enough to allow the set to start.

To resolve this, proper troubleshooting of the power supply, scan circuits, and related areas would have to be done. This is something you would not be able to do at home, unless you have experience in TV servicing, and are set up to do this type of job.

Jerry G. ======

check the picture tube heater elements to see if they are glowing. If not you probably have a bad connection on the crt neck.

Thanks for your replies. I originally thought that the problem was of the usual dry solder joint type but now I'm not so sure.

Switching the TV off and on using the standby buttontakes less than a quarter of a second and it always fixes the picture if only for a little while. I wouldn't expect this if it was a problem with heat expansion of a circuit board. Also the room temperature doesn't seem to make any difference. The connector at the neck of the tube still glows when the tube has gone off.

I don't know too much about electronics, I'm a former electrician so I have a grasp of the basics but could it be something to do with a part of a circuit discharging when the picture is switched off? Or voltage regulation perhaps? I told you I don't know too much electronics!

I had hoped that the fault would be of a type that someone would recognise as a particular one. Otherwise I will have to take Jerry G's advice and take it to a repairer.