You can take it to a TV doctor and have it investigated -or - if you are confident enough investigate it yourself.
An area of circuitry has a component that works OK when it's warm but not when it's cold - it is possible to discover which component with specialist Freezer Spray.
Operate the machine with the covers off and wait for the fault to go away - then squirt selected parts of the circuits with the can of freezer to try and make the fault come back. You might use a hair dryer to make the fault go away again and the freezer on a smaller area until you can narrow it down to a particular component - and change it - but beware...
I have used this technique on computer faults in the past but things are not always as they seem... sometimes after changing the component that makes the fault come on when you freeze it - the fault is still there!
The "cooled" component might be working absolutely correctly but just has a characteristic of sending out a signal that varies only very slightly with temperature but the component that receives the signal may be defective and not able to cope with the reduced, cold, signal.
What fun you can have...
Take great care - very high voltages lurk inside conventional TV sets.
Good luck...
Peccavi, November 2009
