Scanners

My Microtek V 310 scanner has decieded that the front Green LED keeps flashing and wont go solid. Yet the lamp is working and green LED on SMPSupply is on also.
What causes the lamp to remain flashing ?
Searching the web they mention warmup. (Please explain the full theory of operation).
What warms up inside who can tell me and give me what the fault might be?
Even when unplugging the scanner Port A and testing the scanner, still the light wont stop flashing.