HP LaserJet 4M+
I had a sense that something was wrong starting a few weeks ago. This printer is little used, I turn it on for a few minutes once or twice a week. Now, I’ve had an HP4M printer since 1995 or so, but this HP4M+ I actually found set out on the sidewalk 5 years ago. I loaded it up in the back basket of my bicycle and brought it home. It was dirty, obviously hadn’t been used for a while, I cleaned it up and got it working fine. LED display now is completely blank. A couple of weeks ago the LED display started acting a bit weird. Instead of the usual message when it was ready: [ 00 READY ] the LED said: [ 000READY ] Otherwise it seemed OK, but as I say, this printer gets little use and probably turned it on only 3-4 times until last week, when I turned it on, it made the usual noises during the self test, and everything looked and sounded as normal except that the LED display was blank. I printed my stuff OK from my PC (i.e. it WAS READY). I did the same today, LED is still blank but it prints without issue. So, what is likely the problem? Thanks for help! PS My old HP4M from 1995 has an issue (I think failing PSU), so I’d like to fix the HP4M Plus if reasonably possible.

Experienced technical support provide their insights in answering this question :
Check the connections to the display and the DC controller. Could be either a bad controller or a bad display. Unfortunately, you can’t swap either with your HP 4.

How to Identify and Fix Common printer Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced technical support :

Make sure that the printer is properly connected to a suitable power source. Press the Power button to turn off the printer. Disconnect the printer`s power cord from any power strips or surge suppressors and then plug it directly into a grounded wall outlet.
There are numerous possible causes for a printer that`s randomly producing blanks. The most common ones are empty ink cartridges, improper cartridge installation, and congested nozzles.
A Print Screen button not working the way it should is often the result of physical damage to the button itself or a keyboard that needs a firmware update. An out-of-date Windows operating system can also cause Print Screen to malfunction, as can a lack of system storage and free memory.
HP inkjet and ink tank printers without a touchscreen

Use the Cancel and Wireless buttons to restore Wi-Fi setup mode. Press the Cancel button to ready the printer. Press and hold the Wireless button and Cancel button simultaneously until the Power button blinks.

Restart Your Printer and PC

Many times, a simple reset can resolve the issue. Restarting your printer and rebooting your PC may clear up the issue that causes your printer to print blank pages.

Ghost prints happen when the drum or fuser unit within your printer become faulty. Because a fault with this element won`t heat the particles of the toner to a high enough temperature, the marks being made on the paper are much lighter in colour and appear more faded than typical documents.
Make sure your devices are properly connected with each other, and the network or the cable you use to connect these devices is normal. You can also try restarting your HP printer. Turn it off completely and unplug the power cord, leave it for a couple of minutes, and then plug the cord back and power on the printer.
The screen`s LCD connectors may be loose. There is a critical system error. You may have installed incompatible apps. The phone may have been overcharging for a long period of time.
Force Restart Computer. If you see a black screen after you hit the power button, try holding it down for about 10 seconds to force your computer to shut down, then turn your PC on. Doing this repeatedly three times, the Windows Startup Repair should run automatically.
What causes ghosting? The most likely culprit is either the imaging drum unit or the fuser unit, however humidity and the incorrect paper type can all play a role in ghosting. Ghosting is often caused by a malfunctioning imaging drum unit.
Ghost images, like those created by cataracts, usually are seen by only one eye. Ghost images can occur after corneal surgery, such as LASIK, PRK or a corneal transplant. Most of these problems disappear when the problem is resolved, like after cataract surgery or when the refractive surgery heals.
Reasons why your HP printer has ink but won`t print

This may seem obvious, but it sometimes happens: first make sure your paper tray has paper in it. Misalignment, clogged printheads, faulty data communication or insufficient ink levels can also be sources of the problem.

When your printer runs a blank page between every printed page, the problem is most likely related to your drivers. Outdated drivers are the main reason for errors & system issues.
First, check your printer settings on the file or picture your trying to print. If your page is setup to print in “grayscale” it will only print in black and white. Change the setting to “default” so it will print in color. If your settings look good from the start, the cartridge may just need to be primed.
First, check your printer settings on the file or picture your trying to print. If your page is setup to print in “grayscale” it will only print in black and white. Change the setting to “default” so it will print in color. If your settings look good from the start, the cartridge may just need to be primed.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

LED display is blank
ANSWER : Check the connections to the display and the DC controller. Could be either a bad controller or a bad display. Unfortunately, you can’t swap either with your HP 4.

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HP LaserJet 4M+

Blank Display
ANSWER : Most likely cause would be the controller board. That requires a little bit of disassembly to get out. Around $100 or so for the part.

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HP LaserJet 4M+

HP Laserjet 4 Plus LED display dim
ANSWER : My HP Laserjet Plus’s LED display went blank around 6 weeks ago. It had been acting strangely for about a month, when ready, instead of the usual 00 READY it would display 000READY, which got my attention. Well, it suddenly went entirely AWOL. The service manual said to check:

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HP LaserJet 4M+

Display blank
ANSWER : I think PCA just means Printed Circuit Board Assembly, it can also be listed as PCB but either way it’s the same thing.

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HP LaserJet 4M+

HP Officejet 860 printer printing blank pages
ANSWER : First check the exact ink levels, replace if any one are low or empty.

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HP LaserJet 4M+

HP Color Laserjet blank pages – only jetdirect page
ANSWER : What about the engine test? To do that, drop down the front tray. Feel around on the left side at the top and you’ll feel a little plastic dongle. If you lift up on that it will initiate an engine test page. That will be a page containing lines of each color.

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HP LaserJet 4M+

4F displayed on Brother 990CW printer?
ANSWER : That’s a printhead error.

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HP LaserJet 4M+

printing blank pages
ANSWER : You can’t let an inkjet printer sit that long. Try flushing the heads. Take out all the ink tanks and to the right of the assy. you will see a plastic lever. Lift it and it will release the heads. Take it to the sink and using hot running water, flush it from top and bottom several times. Then blot it dry and reinstall.

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HP LaserJet 4M+