Hello :

I think it's the bulb .. Here I'll tell you how to replace it :

1. Make sure that your power switch is off and that the power cord is unplugged from the electrical socket.
   It is also wise to unplug any other cables and label them in order to restore them in the right way once the lamp is replaced.
   
2. In order to see the lamp, remove the access handle on the outside cover. You may need to use a screwdriver.
   
3. Pull out the used lamp and clean the relevant parts using micro fiber products and not paper.
   Please note that in some projectors a small inside filter should also be replaced.
   
4. Insert the new lamp into the projector carefully avoiding touching the glass of the lamp itself.
   Touching the lamp will deposit skin oil that will likely damage any new lamp during use.
   
5. Reassemble the access panel, repluge the cables and power up the projector.
   

• new projector lamp
• screwdriver
• micro fiber duster

• avoid touching the bare projector lamp

There is a shot off circuit that shots off to prevent the lamp from getting hot.. This circuit can be malfunctioning ...

But I'm thinking that the bulb can need replacing ,, or that the solders close to the bulb need resoldering.. In any case it will cost you a whole hell of a lot cheeper to repair it rather than a new one..

That the only reasons I can think off ,, off hand without exactly examining the machine..