What is the fault for Sagem Axium HD45S?

Set has started to go to standby without coming on.
Left for a few days and came on OK for the next few days now has reverted back to going on to st/by. .
Checked inside and very clean - no fluff or heavy dust covering. On normal start -light comes on and disc motor can be heard and after 40 secs screen comes up. Now, disc hum but no light and goes to st/by at 60 seconds... Lamp replaced recently but faulty start up had already begun but usually responded on second attempt.. Any clues please