HP LaserJet 1100/1100A Printer blinking light, Faulty paper exit flag

Blinking yellow (amber) light might be due to a faulty paper exit flag sensor. This is a spring loaded flag which is supposed to be up until there is paper pressing it down. If your flag is down even though there is no paper present you will see the blinking light when you power your printer on. Watch this video for a simple solution with very minimal disassembly. You can actually see the flag and check to see if it is in the correct position by just opening the cover and looking at the two lowermost white rollers. The black flag is just to the right of the left side white roller. It should be UP and with the weight of a piece of paper on it, it goes down.