Question about HP LaserJet 4 plus Printer

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50 service problem

 HP LaserJet 4 plus Printer Problem


How can I solve the Problem of (50 service)?


When I power the printer up it goes into warmup and then issues message '50 service' with the 50 flashing. The cartridge toner is fine as it hasn't been used much. I do not have a manual to tell me what this message means.

Thank you in advance



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Re: 50 service problem



Please try below solution.


ERROR 50 - Service

A 50 service error can be either a temporary error or a permanent problem requiring service.


Temporary Error: Power off for 20 minutes to allow the capacitor on the DC controller to fully discharge. If you don't allow this capacitor to discharge, you will still get a Error 50 even if you have fixed the problem.  This may clear the error - either temporarily or permanently. If it clears the error it was most likely caused by a low power problem  i.e. low line voltage causing the power supply circuits to drop out of regulation. Low/unstable power (low line voltage, brownout condition).  If it doesn't clear the error you may have one of the problems listed below


On the HP LaserJet 4L/4ML, errors are indicated by a series of indicator lights.  This printer has four lights, Paper Jam, Paper Out, Data, and Online.


If all four lights are on, press and hold the blue panel button to display a secondary light pattern.


An error 50 is indicated by the ready and error lights with the blue panel button pressed.

Turn the printer off for 15 minutes to see if the error clears.  If not, you will need to remove the fuser assembly to perform further checks.  This requires removal of the cover, an unpleasant task, and measurement of the fuser terminals.




For your convienience, I will would like to provide the web link that shows the picture of the scene


link is:


try the things that are mentioned in web link. If the issue persists, then Printer needs to serviced.


I hope that this should resolve the issue for you.


If you need any further assistance, please let me know. I'll be glad to help you.



Posted on Oct 18, 2007

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Hi there!The error code 50 means bad fuser lamp.The fuser is the part of the printer that is fusing the toner to the paper.If you open you back door of the printer you will see two rollers.One pressure and one fusing.Inside the fusing roller is the lamp.When you start up your printer keep the back door open and look if the lamp goes ON.If nothing happens you need to call a service help and to replace the lamp with a new one.If the lamp goes ON but the error is there, that means your heat senor has broken and need replacing.If you have any other questions please replay!!!

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50 error is the fusing assm. You need to replace the fuser then the error will go away.
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HPLaserjet4P - printer service 50 -


A 50 Service error is a fuser error. Turn the printer off for 5 to 10 minutes, then turn it back on. If the error is still there, I think your going to need to make a service call you can try reseating the fuser, but be sure to let the fuser cool completely before touching it.
Good Luck the HP Laserjet 4p is a great printer.

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50 service flashing on display screen

If the display panel reads 50 FUSER ERROR, CYCLE POWER, turn the printer off for 15 minutes. This allows the capacitor that is responsible for signaling this error to discharge. If you don't wait 15 minutes you will continue to get this error even if you have replaced the fuser. If it continues to show the error, then you need to replace the fuser. It is easy to replace.
The fuser maintenance kit is about $119. on the web.
If I could be of further assistance, let me know. If this helps or solves the issue, please rate it.
Thanks, Joe

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Error message on startup

The fuser unit could be the causes. But you can try this, power off the printer & unplug the power cord for 15 to 20 minutes. Power on after 20 minutes and se whether the problem resolves, if it ok, monitor it for a while just to make sure the problem resolves

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