Hp laserjet m603n flashing orange warning light and says "ready" then changes to "please wait...checking printer" sitting like this for days now. When I reboot withought the ethernet cable it boots u

Fatal error., replace formatter board..

you might try a recycled cartridge and have a lot less invested.Sounds like your cartridge is empty.Is print quality bad or light?

Initialization error is usually related to the communication connection. Make sure that the connection is solid. Might want to unplug the cable from the back of the printer and then turn the printer on, comes to ready ? If so the cable or connection might be bad.

Hi Angela,
What is a problem whit printer? Service error 49.xx.xx or?

flshing orange lights may be happends from anything , check the tray u fix the paper well, check any paper jam in ,printer for more truble shoot you can visit www.hp.com

This is a link to HP for your Color Laserjet 2550n instruction manual. Look on pages 97 & 98.
http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c00189910/c00189910.pdf
And for further troubleshooting, try this link.
http://h20499.www2.hp.com/gts/sparks/public/IPG_CLJ2550_All_toplevel_WhatDoYouNeedHelpWith_PUB_EN?lang=en&cc=US&product=Printer&series=na&subseries=na&prodTypeId=18972&prodSeriesId=388394

cartridge sensor eror or cartridge not detect or paper jum

If this is a new printer, chances are you may have left a piece of orange tape some where in the printer, otherwise you may have to remove the transfer belt, power the printer on and wait for it to say that it is missing, replace the belt and power on again, should fix it.

Try putting a piece of paper in tray 1

Hi vgde2004: Here are some things to check.

1. The printer is in manual feed mode.
Possible solution: Change the manual feed setting in "printer properties"
2. The door is open,the media is out,the toner cartridge is installed incorrectly,or the paper is jammed. Check paper path.
3.Fan error
Solution:
1. Check fan cables for looseness.
2. Replace fan assembly