Deccacolour D28N440 - Beeping on Standby

[buttercups]

I've got a rather old Deccacolour D28N440 - the picture and sound has always been perfect, but recently I switched it on and the standby light started flashing and it makes a bleeping sound every time if flashes.

It does not turn on at all and you have to turn if off to stop the beeping and flashing. As it's an old TV cannot find any support so any advice would be greatly appreciated.