hp laserjet 6mp - orange light?

hi all

i have had a hp laserjet 6mp working in the office for years without issue but...

now it has just stopped and the orange light (the top light of the three on the left hand top) just stays on.

i have searched for the user manual to find out what the light means - but i cant find it anywhere so does anyone know what it means?

if i click the round button above it the light next to the "c" (on its side) flash 9 times and then it goes back to the solid orange light.

any help would be very welcome and happy christmas to you all!

as ever
keen to learn..