HP Laserjet 4MP Help required Please!

[TerraAustralis]

My trusty old HP Laserjet 4 MP has acquired a problem which cold resets, I/O resets have failed to fix. Can anyone help please?

I can insert paper manually and get a perfect print. When I print from software, the sheet goes through the printer but sticks with 1/4 of the page projecting from the output roller. The reason it sticks is that a second sheet has started to feed, this despite the fact that only one print was requested in the application software.

If I run a self test via the printer console buttons, exactly the same situation occurs. When the page jams, 13 PAPER JAM appears, I open the drawer and sure enough a second sheet is partly fed for printing. I remove the paper and open the paper tray drawer so another sheet cannot feed and press ONLINE. Briefly the printer shows 02 WARMING UP and pumps out the sheet a little further until 13 PAPER JAM appears again. I repeat pressing ONLINE until the sheet is pumped out completely and I try a COLD RESET. If I close the paper drawer and allow the printer to re-set itself it will try to print the sheet which again jams, and the whole situation repeats itself.

I thought the problem may be software in the computer application or system. So I have deleted all drivers, reset the OS Leopard printer and reloaded fresh HP drivers all without success. I have considered whether a bit of paper is stuck in there somewhere and that may be the case. However sheets do feed through OK sometimes. It is the feeding of the second sheet which causes the problem.

The printer is networked via a D-Link G321 print server and an iMac and a 1.8 MGh G4 connect via WiFi and Apple Talk. This arrangement has worked fine for several years.

The current problem was caused by a user error with a print instruction from the G4 using Microsoft Office which Microsoft Software stated the HP driver was incompatible with Office. That has all been reset. Printer tests have been made with all computers off.

If setting the MP4 to factory defaults does not work, what else can I do?

[Big Al]

This sounds like you need new output rollers. If the paper has exited the fuser but fails to reach the sensor at the upper output roller then you get a jam. After a while these rollers get hard, like an old pencil eraser. The one you most likely need to replace is the lower one. Doing both is a good idea since the upper one will also cause problems sooner or later. Cleaning them will only work for a very short time. Let me know if you need the part numbers.

Al

[TerraAustralis]

OK AL,
The paper projecting from the printer has the complete image on it but the lower part (still in the machine when it jammed), is not fused. It wipes off. Another aspect that is odd to me: why would the printer pick up a second sheet when the software specified one print only?

Is this consistent with your analysis?

4 weeks ago I had exactly the same behaviour and I appeared to solve it by trashing computer printer prefs and doing a cold reset on the HP. The printer worked flawlessly since that period of time until the Microsoft print error report and the situation described above.

Your point about the rollers sounds convincing and after 15 years the rubber would be hardening, but that would not explain the second sheet being picked up would it? Is there another possible explanation to do with software?

[Big Al]

I'm not sure about the second sheet. Worked on a lot of these over the years and used one at home for a long time. What you are describing is a worn feed roller. If you feel it and it is hard and slick then you need to change it, and the upper one too while you are at it. Also strange how it suddenly quits working. The lower one is RF5-0438-000 and the upper one is RF5-0534. Be careful to get a death grip on the "E" clip when you remove the bushings. If it gets loose inside the machine it may take a while to find it and get it out. Sometimes I tie a noose of dental floss on it to prevent this. Also note the bushings have a tab sticking out that keep the bushing from turning in the frame.

The symptom of the upper roller is that the paper will come out with a shallow roll in the top of the sheet as the upper roller is slipping and the lower one still pushing on the paper.

You can sand the roller a little and get by while the parts come. The upper shaft has four or five little gray floppy guides on it. They have to point forward when you put the upper guide back on.

Al

[TerraAustralis]

Al,
You are giving me very good advice and I very much appreciate your comments.

I have a .pdf of a Combined Service Manual 4L - 4Psm.pdf

Problem is the illustrations for dis-assembley etc are as black as pitch and unreadable.

My model is dated December 1993 with a serial number NLCB000817. Older than I realised. Searches with this number on Google get nowhere.

Would you happen to know a link to a good manual file? I am good at mechanical repair but as far as printers go I am a novice. There is no way I am going to take this baby apart without a good factory repair manual.

[Big Al]

If you go to Google and search there are several free sites to download the manual. You really do not need the manual to do the lower roller. Open the back door, the shaft is right there. On the right hand end is an 'E' clip. Carefully remove it. There is a nylon bushing behind the E clip. Slide it out to the right (as you are looking at the back of the printer.) Notice there is a raised area on the bushing to keep it from turning in the frame. Gently pull the right end of the shaft towards you. Don't panic, four little black rollers will fall out. Continue pulling the right end of the shaft towards you. Push the shaft towards the left and slide the bushing and the gear free of the frame and the belt.

Hold the new shaft at that same angle and slip the toothed pulley under the drive belt, position the bushing with the raise area in the slot so it will not turn. Slip each of the black rollers in place in front of the tension springs one at a time. When you have the shaft back in the right hand slot put the nylon gear back in with the raised area in the open slot and put the E ring back on.

I like to tie a piece of dental floss on the E ring to keep it from going PING and disapearing. Then you can cut the floss off. There is no timing on the gear so you do not need to worry about that. I used to clean the crud off the black plastic rollers but eventually discovered it made no difference that I could tell.

The top one is about the same but you have to pull the top cover to get at it. Wait till you have the book or get back to me and I will talk you through it.

Al

[slowhand53]

send me a PM with your email address if you still need the manual.

it's a combined manual covering both the 4 and 5 series

[TerraAustralis]

Thanks Guys.
I would like a copy of the manual Slowhand 53. The free copies I have found do not quite match my model despite the model description so my top is not removed as the manual describes.

Al, and Slowhand53, I shall try and get replacement rollers then may I contact you again please via email.

For security, please go to my website: tonyfostergraphicdesign.com.au click Contact and send me your email addresses in the Contact form and we can better communicate.

[cs_steve]

Quick note guys ... Keep in mind that Terra has a 4MP -- the advice / manuals recommended so far are actually for the 4Plus/5 series, not the 4MP. The old 4MP has a different layout.

I think the copy of the 4MP service manual you have Terra, is going to be your only option. (HP didn't produce an electronic version of this service manual so it had to be scanned in page by page, and the resulting graphics weren't very good.)

As far as your problem, the extra sheet feeding would be from a failing pickup assembly (probably the pickup solenoid sticking and causes the roller to turn an extra cycle)... if you want to repair/replace it you'll need to remove the panels, etc. to access the pickup assembly. Because it is not well supported and parts are hard to come by, this is one model that is sometimes not worth trying to repair.

If you like the size, features of this model, the closest printer upgrade in comparison would be a LaserJet 2300 or similar.
http://www.printertechs.com/printer/refurbished-hp-laserjet-2300.php

[slowhand53]

Quick note guys ... Keep in mind that Terra has a 4MP -- the advice / manuals recommended so far are actually for the 4Plus/5 series, not the 4MP. The old 4MP has a different layout.

I think the copy of the 4MP service manual you have Terra, is going to be your only option. (HP didn't produce an electronic version of this service manual so it had to be scanned in page by page, and the resulting graphics weren't very good.)

As far as your problem, the extra sheet feeding would be from a failing pickup assembly (probably the pickup solenoid sticking and causes the roller to turn an extra cycle)... if you want to repair/replace it you'll need to remove the panels, etc. to access the pickup assembly. Because it is not well supported and parts are hard to come by, this is one model that is sometimes not worth trying to repair.

If you like the size, features of this model, the closest printer upgrade in comparison would be a LaserJet 2300 or similar.
http://www.printertechs.com/printer/refurbished-hp-laserjet-2300.php

Steve-

I have 2 different manuals that clearly state they cover the 4 series. Give me a place to put them and you can double check. I'm just trying to help a fellow tech.

TerraAustralis-

for security reasons, I don't enter info into web forms unless i trust the source (and I don't know you yet). please send email address or a place to upload as a private message here on the forum.

[redcow]

Yes the manual is titled LJ4L/LJ4mL and LJ4P/LJ4MP
And yes the "pictures" look like they were created with a mimeograph machine.

I think that Steve is suggesting that you dump this printer, before it becomes your money pit. Listen to Steve, It's gonna be cheaper to replace the printer than repair it.
And you'll be glad that you did.

[Big Al]

My appologies! Foot is in mouth! The one or two I worked on years ago were 4M+. The 4MP is one that I have never seen. Put it on a stump, paint red circles on it and use it for target practice! Sorry!

Al