Installed ROM into a working HP LJ 4200n, now it does not work, it displays errors "rear door jam" and "cover open".

Paper Jam clearing: copy and paste the link in your web browser...I used to work with these printer's..when they work great, when they don't, not so great..

https://www.manualslib.com/manual/949165/Hp-Laserjet-5000.html?page=84

Clearing Paper Jams If the printer's control panel displays a paper jam message, look for paper in the locations indicated in Figure 22, then see the procedure for clearing the paper jam. You might need to look for paper in other locations than indicated in the paper jam message. If the location of the paper jam is not obvious, look first in the top cover area.When clearing paper jams, be very careful not to tear the paper. If a small piece of paper is left in the printer, it could cause additional jams. If paper jams are a recurring problem, see page 78.(A paper jam message might also display if the rear door is open.)

The top cover of the printer must be opened and then closed to clear a paper jam message.Paper jams can occur at the following locations:Output areas(top and rear)Go to page 75.

Loose toner might remain in the printer after a paper jam, but thetoner should clear after a few sheets are printed.

Thank you contacting FixYa for your printer inquiry.
This error is associated with either a sheet of paper blocking the paper path or a partial piece of paper that blocks path or trips a sensor. The printer will usually throw up a error code 13.XX on the display and the XX is a number that will indicate where in the paper path this error most probably occurred. Just follow the steps for your error on the below chart.
This link will take you to the user guide which will be helpfull identifying components and providing guidelines for most of the helpful hints and things you will need to know about this printer.
http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c00218691/c00218691.pdf
Locate your error on the matrix below and follow the steps. Comment back if you need more help. Thank you again for contacting FixYa.
TF
HP Laserjet Error Codes 0 - 19 Message on printer Display Panel What it means. What to do. 13.XX PAPER JAM [LOCATION] Media is jammed at the specified location (and possibly at other locations). If the message persists after all jams have been cleared, a sensor or sensor lever might be stuck or broken. For all jam messages, do the following: 1. Remove jammed print media from the specified location. Check the entire paper path for other pieces of media in the path. 2. Open and close the top cover to clear the message. 3. Check sensors and flags in the paper path for proper operation. 3.0 PAPER JAM [LOCATION] A non-specific paper jam occurred. 1. Remove jammed media from the specified location. 2. Verify the paper tray is fully closed. 3. Inspect and/or replace the feed and separation rollers. 4. Ensure there is no obstruction in the path, such as a torn piece of paper. 5. Open and close the top cover to clear the message. 6. Check sensors and flags for proper operation. 13.1 PAPER JAM OPEN INPUT TRAYS Paper-delay jam at paperfeed area. 1. Ensure that paper trays are loaded and adjusted properly so media can feed from the tray. It might be necessary to reduce the stack height of media in the tray. 2. Check the input area for obstructions such as media in the path. Also check to see if the registration assembly damaged or unseated. 3. Replace any defective sensors or flags. 4. Verify the media meets the specifications. 5. Check the pickup feed and separation rollers for unusual wear. Replace as needed. 6. Rotate the media in the input tray by 180° and/or turn it over On NX engines this is most likely the fuser flag or the ACPM. The ACPM has a photosensor hard-wired to the back of it. 13.10 PAPER JAM CHECK DUPLEXER Jam at duplexer. 1. Check the duplexer and the rear area of the printer for obstructions or damage. 2. Check the duplexer for proper operation. Replace the duplexer if a sensor is defective. On a 5si, 8000, or 8100 series laserjet a Duplex Jam can be caused by a tray 2 and 3 feed assembly failure. 13.14 For Laserjet 5si. This error is caused by a defective paper control PCA Replace paper control PCA. 13.2 PAPER JAM OPEN INPUT TRAYS Paper-stopped jam at paper-feed area. 1. Check the input area for obstructions such as paper in the path. Also check to see if the registration assembly is damaged or if the transfer roller is out of place. 2. Replace any defective sensors or flags. 3. Ensure the media does not exceed the maximum length. 4. If multiple sheets are feeding, it might be necessary to fan the media and reduce the stack height. Also, replace separation pad. 5. Verify that the fuser is properly installed. On NX engines this is an input jam. 13.20 PAPER JAM CHECK REAR DOOR Media stopped in the paper path during power on or when the top door was closed. 1. Remove all media in the paper path, and then open and close the top cover. 2. If the message persists after all media is removed: Check if media is jammed in the prefeed area. Replace any defective sensors or flags 13.21 DOOR OPEN JAM The top cover was open while printing. 1. Clear the jam and close the top door. 2. If the message persists, check the top door switch for proper operation. 13.5 PAPER JAM CHECK REAR DOOR Paper-delay jam at fuser. 1. Check the transfer roller and small media belt to ensure they are operating and can feed print media. 2. Check the paper path for obstructions at the transfer roller, toner cartridge, paper feed assembly, and fuser. 3. Replace any defective sensors or flags. 4. Turn the media stack over and/ or rotate it by 180° in the input tray. If still persists - replace fuser, then DC controller. 13.6 PAPER JAM CHECK REAR DOOR Paper-stopped jam at fuser. 1. Check the paper path for obstructions at the fuser and output/delivery area. 3. Replace any defective sensors or flags. 13.99 PAPER JAM [LOCATION] A non-specific paper jam occurred. 1. Remove jammed media from the specified location. 2. Verify the paper tray is fully closed. 3. Inspect and/or replace the feed and separation rollers. 4. Ensure there is no obstruction in the path, such as a torn piece of paper. 5. Open and close the top cover to clear the message. 6. Check sensors and flags for proper operation

paper jam on hp laserjet

Please get the correct driver here : www.printcountry.com/drivers.asp
www.opendrivers.com/.../printers-free-driver-download.html
www.driversdown.com/driverslist/r_4_1.shtml
Regards, Jay__9iujgt4

50.2 indidicate a possible faulty fuser or lack of power to the fuser.

If you have another LaserJet 4200n (must be same model, verify under the toner cover, by the serial #), swap the fuser assemblies by removing the back door (rear output access cover) and then releasing the fuser with the 2 blue locking tabs. When you reseat the fuser, it should click into place on both sides. Re-attach the door and test...if problem (error 50.2) moves to the other printer, you have a failed fuser, if issue remains on original printer, it is a power supply issue.

Hi,
As i can understand whenever you try to print with rear door closed printed page should come on top from top output roller however paper gets jammed.
Solution:
Try to print a page using rear door open and it should come out from the rear drop down tray it printed page comes out successfully with rear flap open than paper gets jammed at top due to faulty top output roller.
However if the paper gets jammed at fuser with rear door closed than it is issue with fuser in that case you need to get fuser replaced at the same time replace 20 tooth gear next to fuser.

Thanks and Regards
Neeraj Sharma

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simply connect the rj45 cable and create the printer using hp network printer software. you can download it from the hp website

What is the exact error message shown on the display ?
Does it makes any strange noise when you start it up ?

Try this linke below.
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=110&prodSeriesId=411171&prodTypeId=18972&prodSeriesId=411171&objectID=c00642524

Or i cut and paste text, but you should view pictures. If you cannot get to it from link. Try typing "Paper jams alternating between front and back door" It should be first link from HP about a 3550.

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HP Color LaserJet 3500, 3550, and 3700 Series Printers - Paper Jams Alternating Between Front and Back Door Issue Description Customers may see paper jams error messages with no paper seen in the paper path. The message will alternate between check the front door and the back door. Workaround The release lever engagement tabs on the rear door can be bumped into the in-correct position. The purpose for this tab is to re-engage the fuser release levers as the rear door is closed. When one or both of these are left in the in-correct position the printer goes into a cycle of alternating between a "Jam in the Front Door" message and "Jam in the Rear Door" message. There is no paper present in the paper path when this happens. When a customer gets the "Jam in the Front Door" message and opens the front door, no paper is found. After the customer closes the front door, they get the "Jam in the Rear Door" message. When they open the rear door, find not paper (even pull out the fuser), and close the rear door, they get the "Jam in the Front Door" message. This cycle will continue

Placing both engagement tabs in the "Correct" position solves the problem and allows the print job to continue.for as long as the customer is willing to keep checking.