Laser printer repair tips for HP laserjet printers

HP Laser Printer Tips

For repetitive print defects always make sure to rule out toner cartridge even if it is brand new. If you use recycled toner cartridges make sure the company recycling them does not just refill them.

If the inside of the printer has toner all over your cartridge is probably bad and is spilling toner

When moving or shipping your printer always remove toner cartridge before doing so.

Pickup rollers should have rough surface if they are slick, very smooth, they should be replaced. HP recommends cleaning with cloth and warm water, if this works it usually will not last long. You can use alcohol pads as last resort to get back in service.

Your eyes and ears are your best troubleshooting tool, look closely, use a flashlight, listen and try to determine if the startup and printing sounds are normal. Compare with known good printers and parts if you have this option.

HP Laser Printer II, III	Most jamming problems are the due to worn gears in fusing unit. To verify fusing unit is bad, with printer on, open cover and push and hold down switch as shown on left, the motor should turn all drive gears, release and repeat. To test gears of fuser push down spring loaded lever at the same time.
50 Service error	Check fuser lamp if ok replace ac module
	If both of these are ok replaced fuser to dc control bd cable
13 Paper Jam	If paper is not being picked up replace Pickup Roller
Print starts too low on 2nd OK on first	Paper control board that screws on DC power supply, try cleaning sensor first.
16 Low Toner Error	Replace high voltage power supply if not the cartridge.
Horizontal Lines	Replace Laser Scanner assembly
52 Error	Most likely laser scanner cable, possibly laser scanner
Jams out top ok to back	Delivery coupler assembly
Service Manual Part #	33449-90906

HP IIISi, 4Si Laser Printer

Canon Based NX Engines

13 Paper Jams

Replacing fuser and separation rollers will take care of most problems with these printers

50 Service Error

Although the lamps in the fuser usually don't go bad, they can open and bring in this error, more often the triac inside the AC module has blown causing the fuser to never heat up

Noisy - Squeaking

Most likely rollers in job offset assembly, but could also be caused by contacts in fuser assembly

Service Manual Part #

C2010-90939

HP 4V, 4M Laser Printer

Canon Based BX Engines

Intermittent 50 service error

The fusers in these printers run very hot if you get 50 service errors first power off let cool down and try again. If you have to do this often the thermistor in the fuser is probably bad.

Jams from optional 500 page lower tray

Replace roller assembly

Service Manual Part #

C3141-90929

HP 4, 4M, 4+, 4M+, 5, 5N, 5M

Canon Based EX/EX+/EXII Engines

50 service error

Fuser Lamp probably open, or toner build up on thermistor also inside fuser. Order rebuilt fuser

Accordion Jams

If paper comes partially out the top of the printer and jams or fan folds the paper at the bottom.

If paper fan folds inside the fuser and never comes out the top of the printer.

41.3 Error

Reseat electrical connections especially on Laser Scanner and DC Control board. Swapped Toner cartridge

52 Error

Replace Laser Scanner

Poor quality print and/or 13 paper jams

Replace Maintenance kit.

HP 5Si Laser Printer

Run paper path test from control panel on all trays even manual tray, don't forget that's tray 1.

13.x Paper Jams

The "x" code can only be deciphered using the service manual. It will indicate which sensor has timed out that brought the error in. In any case replacing the fuser and 6 feed rollers will take care of most jamming. If it doesn't you will need to replace the Paper Input Unit (RG5-1852).

43 Error

Not listed in service manual, will not show up on display. You will only know it has occurred by looking in the error log. We have found bad memory to cause this error not the formatter board.

Printer goes off-line when printing from network

This is what the printer is supposed to do when it receives corrupted data. Your Jet-Direct card is not bad! .

Service Manual Part #

C4077-99015

HP 5L and 6L Laser Printers

Canon Based AX Engines

Top and bottom LED's remain on with test

Fuser error, these printers use heating element which will need to be replaced either

Paper jams

Replace pickup roller assembly and separation pad kit.

Service Manual Part #

C3990-99001

HP IIISi, 4Si Laser Printer	Canon Based NX Engines
13 Paper Jams	Replacing fuser and separation rollers will take care of most problems with these printers
50 Service Error	Although the lamps in the fuser usually don't go bad, they can open and bring in this error, more often the triac inside the AC module has blown causing the fuser to never heat up
Noisy - Squeaking	Most likely rollers in job offset assembly, but could also be caused by contacts in fuser assembly
Service Manual Part #	C2010-90939

HP 4V, 4M Laser Printer	Canon Based BX Engines
Intermittent 50 service error	The fusers in these printers run very hot if you get 50 service errors first power off let cool down and try again. If you have to do this often the thermistor in the fuser is probably bad.
Jams from optional 500 page lower tray	Replace roller assembly
Service Manual Part #	C3141-90929

HP 4, 4M, 4+, 4M+, 5, 5N, 5M	Canon Based EX/EX+/EXII Engines
50 service error	Fuser Lamp probably open, or toner build up on thermistor also inside fuser. Order rebuilt fuser
Accordion Jams	If paper comes partially out the top of the printer and jams or fan folds the paper at the bottom. If paper fan folds inside the fuser and never comes out the top of the printer.
41.3 Error	Reseat electrical connections especially on Laser Scanner and DC Control board. Swapped Toner cartridge
52 Error	Replace Laser Scanner
Poor quality print and/or 13 paper jams	Replace Maintenance kit.

HP 5Si Laser Printer	Run paper path test from control panel on all trays even manual tray, don't forget that's tray 1.
13.x Paper Jams	The "x" code can only be deciphered using the service manual. It will indicate which sensor has timed out that brought the error in. In any case replacing the fuser and 6 feed rollers will take care of most jamming. If it doesn't you will need to replace the Paper Input Unit (RG5-1852).
43 Error	Not listed in service manual, will not show up on display. You will only know it has occurred by looking in the error log. We have found bad memory to cause this error not the formatter board.
Printer goes off-line when printing from network	This is what the printer is supposed to do when it receives corrupted data. Your Jet-Direct card is not bad! .
Service Manual Part #	C4077-99015

HP 5L and 6L Laser Printers	Canon Based AX Engines
Top and bottom LED's remain on with test	Fuser error, these printers use heating element which will need to be replaced either
Paper jams	Replace pickup roller assembly and separation pad kit.
Service Manual Part #	C3990-99001