HP lj5550dtn got a horizontal line in the middle

[fort mac]

the line is on every paper printed; printed PQ diagnotics, the line apppears on each color page, so the cartridge errors could be ruled out.

Swapped the fuser, cleaned the static discharge comb, OHT sensor, spilled toner etc. Still the same.

Did Full Calibrate a few times, the line became thinner, but still appears there.

Any suggestion is welcome.

[redcow]

What colour is the horizontal line?
If you run 'paperpath test' is the line there? and what colour is it?

[fort mac]

What colour is the horizontal line?
If you run 'paperpath test' is the line there? and what colour is it?


yeah. the line is always there. light gray color; thin and straight line.

Ran Full Calibrate 6, 7 times, the line gets thinner, but still there.

[fort mac]

What colour is the horizontal line?
If you run 'paperpath test' is the line there? and what colour is it?


some people suggested that i cleaned the laser unit inside. I don't know how to do that in that specific HP Lj. anybody got some experience?

[redcow]

Run the cartridge test. Pull all but the black. Run paper path test. If the lines are there...put the black in the next lower slot and rerun the paper path test. If the line is gone the black's home slot needs to be looked at. If the line's still there pull the black and replace it with the yellow. Test it again. No lines..the black is bad.
et cetera, etcetera

have fun