Stupid User Error Code 54.2 on HP4550n

[majoranne]

I was trying to troubleshoot poor print quality (vertical areas of, light to no printing, on both color and B&W documents). First I replaced toner that was almost out--cyan and magneta. Then I replaced the drum kit. Those changes helped the color prints, but not completely, and did not help B&W prints at all. (I tried to upload an image here, but that doesn't seem to have worked.) Now the real trouble begins:

I swapped the brand new cyan toner cartridge for the black toner to see if that would work. I could not get the black toner to go into the cyan slot, so I left that slot empty and told the printer to "go". After a "this-isn't-right" grinding sound, the laserjet gave me the 54.2 error code. I shut down and powered back on--same error code. The only accessible toner cartridge (from the top cover) is Yellow--and I can't remove it. It seems stuck on the right side in a slightly rear position. Of course, I can't get the printer to rotate the cartridges for me to access the empty slot, either. Is there any other thing I can do at home with this problem?

[cs_peter]

You might want to try looking for an obstruction. You can make that easier by manually releasing the carousel brake and removing all of the toner cartridges. The error simply indicates what you already know, which is that the toner carousel is not rotating.
If you can't find or remove an obstruction, then you probably need to replace the toner carousel. Generally speaking that is probably more expensive than buying a replacement printer.

[majoranne]

Thank you, CS Peter. The problem was the Cyan cartridge has a tab to prevent it from being installed in the black slot, which I (didn't quite)force. I was able to reset the carousel brake and reset all the cartridges.

Now I only have my original problem: Why do I get vertical bands with light print, particularly in black and white printing? I have tried cleaning whatever I can reach and "rotating" the black cartridge. HP seems to want to blame the paper, but we've had two different brands with the same results.

[redcow]

Try replacing the ITB.
I didn't read where you replaced it.