Mitsubishi Diamond Pro 21TX monitor

Please can someone advise on how to fix my monitor. The top half of the display was fine but the picture then narrowed inwards towards the bottom. There was also about 1" of black at the bottom, covering part of the screen (windows) information. After a short time faint interference lines became apparent with a slight shaking, then the picture disappeared altogether. The display was better when starting from cold and gradually got worse over about 4 minutes. I'm guessing capacitor breakdown, but which one? - any more scientific diagnosis would be most welcome. Thanks