Why does my HP 1020 laserjet printer show 3 flashing yellow lights on the control panel when I start it? -

When I try to start my HP 1012 LaserJet printer, it shows 3 flashing yellow lights on the right side where the control buttons and lights are instead of the usual green light, which means it s ready to print. I ve lost my HP instruction booklet. HP did not respond to my email for help. Any helpful advice much appreciated!

Interesting as the HP website http://h10025.www1.hp.com/ewfrf/wc/docum… shows it as having 2 LEDs not 3. That link is to the status lights trouble shooting page fo rthe laserjet 1020 plus . . .