Had the same problem. If your handy with a screwdriver take the back off the set, unplug it first. Follow the mains lead to the power supply board. Look at the capacitors. They are the round blue/black things with silver tops. I had two of them with the tops bowing upwards. They should be flat. The value on mine where 4700uF 6.3Volt. A search on ebay showed loads on sale in pairs. So it must be a common fault.
If your handy with a soldering iron or know somebody who is, change both. Take note (photos) of the connections if you unplug all the leads and take care to solder the new capacitors positive and negative connections the right way round or it may go bang.
Cost £2 some time and solder. Result...
NAE
November 2014