LSU ERROR shows in display panel

A problem in the LSU (laser scanning unit). Make sure all cables are properly connected to the printhead. If correct, replace the printhead.

For Further Assistance, please contact Lexmark Technical Support.

LSU REFERS TO LASER SCANNING UNIT, PLEASE CLEAN THE GLASSES OF LSU, OR REPLACE THE SAME.

LSU stands for Laser Scanner Unit. Depending on the model this should come up only if the services used required scanning such as copy, fax sending, scanning.
nevertheless if this is a continuous message you might need to check the connectors within the scanner which I advise an field call.

Hello my friend this is Laser Scanner Unit error and this is probably cause if the polygon motor in the LSU does not rotate.The LSU’s laser beam is
functioning properly.You can try unplugging the machine for 3 minutes and plugging back in before you do anything else.If this does not fix it you will need to have it serviced.

D is for Duplex. You can print at both sides of the paper. N is for Network. It means that your machine is equipped with a network Interface.
The display should say "READY" when finishing the initialisation process. Try connect a computer and see if it will print. There is a small pin hole at the left side cover. put something small inside that hole and press the hidden switch. That should start a "Engine Test". The printer will print a single page with horisontal lines. If the test page comes out perfect, it's probibly something wrong with your Operator Panel/Display. If you are thinking about replacing the panel/display, here's the part# RM1-0511-000CN

lsu stands for laser scanning unit. it tansfers the image onto the transfer drum, common problems are horizontal sync, i would suggest a replacement lsu

LSU ERROR

LSU Error is showing the printer and is in non working condition

The Laser Scanner Unit or LSU is what writes to the surface of the drum. The glass above the cartridge inside the machine could be dirty. The mirror motor in the LSU could be bad or needing cleaned so it spins better. Laser diode could be bad.

if it's a vertical line in scanned pictures, it's probably a dust bunny on the scanner head, if it's only on printed pages, it's probably a dust bunny on or in the laser assembly or between the laser and the photosensitive drum. if cleaning doesn't get rid of it, you could have a defective scanner head or laser assembly, or a scratch on the photosensitive drum.