I refilled toner of my Lexmark E120 (since it said it was out of toner) and it worked fine untill few days ago when I got status report: Missing or defective catridge. Could this mean it's out of toner again? I read on this site that a lot of people have problems after refilling because chip has to be replaced as well (which is unfortunately not possible since we somehow misplaced original catridge).

Good day.
First try to print a print status report. Here are the steps:
1.Push setup menu button, that would be the wrench icon. 2.Push the right button to navigate until you get to the Tools Menu 3.Tools Menu>Push button for Printer Status Report
This will give you the accurate ink levels on your printer. If it still shows low ink based on the printer status report, you have to reseat the ink cartridge and make sure the orange tape near the HP Logo on the ink cartridge has been peeled off.
If the report shows ink levels are fine, then that status report on the front panel is just a false report. Try powering off your printer and powering it back on again. As long as you don't have print quality issues, you should be fine.

My printer is not responging to the pc.

The lexmark cartridge number is LEXMARK E120 PRINT CARTRIDGE 12015SA

You may still be able to do a printer selftest page.

Press the large button on the printer.

Look at the pages for

Toner
Imaging unit

The Imaging unit may be at end of life.

This is the drum unit and collects the waste toner.
Whilst you can just reset the drum counter (see user guide for this E120, it can lead to problems if you don;t replace the drum unit. I've seen E120 drum units packed full of waste toner, to the stage where they won't take any more, and it just spews all over the mechanism. It's a very small waste collector (but its also a very small printer, and relatively low capacity toner cartridges (1k, or 2k).

Remanufactured drum units for E120 can be found on the usual internet auction sites.

When you replaced the photoconductor, did you go through the procedure to reset the photoconductor counter ?

There's no chip on the photoconductor, so you need to reset this manually


Photoconductor Reset Procedures:
Step 1: Open the front door and hold the
Cancel button until all lights begin to cycle.

Step 2: Close the front door. The warning
clears and the counter resets to zero.

Step 3: Press Continue to resume printing.

Probably the chip on the cartridge that is either faulty, or hasn't been replaced

Besides refilling the cartridge with toner there is a chip in it that you should change so the printer will know that a new cartridge is installed.

In their determination to keep you purchasing their ink whether you like it or not, Lexmark has circuitry built into their ink cartridges that based on measured use tell the printer when the cartridge theoretically should be empty, whether it is or not.

In the case of the black cartridge they are somewhat more lenient than in the case of the color cartridge. Eventually, when the circuitry tells the printer that the black cartridge should be empty it will continue to be refillable, and work, but will present the owner with annoying messages ranging from "you're using an unauthentic cartridge" to other things. The best thing to do in this case is to check the box that pops up telling it not to continue giving you the annoying messages. This works, but eventually may start again, after which you again check the box telling it to stop. It's quite livable though.

In the case of the color cartridge the built in circuitry will eventually tell the printer that the cartridge is empty, even if it's not because you have properly refilled it, and it simply will not function any longer. You've just wasted your ink. Natually they don't want to see you destroy your printer, which costs less than purchasing only two of their 2400% profit ink cartridges. Good luck.

my printer is not working so please tell me how can i make it work and may be how to set up

clean the electrical contacts between cartridge and printer.