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Introduction To HP Laser Printer Repair and Troubleshooting

Updated: Jul 25, 2019

Introduction To HP Laser Printer Service Support and Troubleshooting WHAT IS TROUBLESHOOTING? We think of troubleshooting as figuring bad definition, but its implications physical act. Frequently, they'll call expecting a dispatched technician to diagnose printer problem without any input from them. "Here's the machine. Fix it!" they seem to be saying.

Introduction To HP Laser Printer Repair and Troubleshooting
In the real world, laser printer troubleshooting is a complicated, coordinated set of skills that, when properly applied, results in restoration of the machine to proper working figuring out what's wrong and fixing it.

Troubleshooting results when order available information is processed with knowledge and common sense To accomplish good, effective troubleshooting, you must start with a competent technician, ideally, a competent, experienced technician.

Competency, however, is more important than simple experience; experience is overrated if the technician doesn't approach the diagnostic tasks competently. And although competency can be developed with experience, at least a modicum of training is needed to focus his experience properly. Most printer techs practicing today are untrained or self trained, and their customers suffer as a result.


Experience fails when there is a need for specific information. If you don't understand the theory, an infinite number of observations may fail to teach it to you. The next article describes how a printer works and offers dozens of examples there essential information is all but impossible to "learn from experience." To be competent at troubleshooting, you must, at a minimum, master this information, understanding how impulses received from the host computer result in a properly formatted image on the page.

When you encounter a defective printer without having this understanding, you are either remembering a previous success or you're simply guessing-you aren't troubleshooting. Troubleshooting begins with a firm body of theoretical knowledge of "what is supposed to happen."

While in the training process, spend as much time as you can with the printels. Trigger Self Tests and shut your eyes while the machine proceeds. Listen carefuly to every nuance of sound and silence. Familiarize yourself with the sounds of healthy printers, so that when you encounter those same printers issuing different sounds, you'll hear the difference and know where to start looking for the problem.


Troubleshooting is transnational. The customer has something you want (money), while you have something the customer wants (the ability to repair). If a trade can be arranged, everyone can be happy. That's what you want-a win-win deal.

Unfortunately, most techs cut their chances in half by handling customer inquiries incorrectly. A customer will call with a question, and the tech will answer it!The customer then proceeds to ask for service, to call someone else, or to fix the machine himself with the information the tech gave him. And what can be done about it? Nothing. The tech hung up before learning who the prospect was.

I believe everybody in every company is a salesman for the enterprise that employs them. Consequently, everyone needs to focus on three fundamentals:

  1. Winning customers

  2. Satisfying customers

  3. Helping those whose main job is either # or #2 above.

When a customer calls, before they are given any information, information must be demanded of them. You must get their name and their company's name, address and phone number. Make it a routine. Most customers won't bat an eye, but if you're concerned say, "We frequently have trouble with our phones, and I want to be able to get back to you and help you out if we're disconnected."


Customers want concise answers. They want to know what's wrong with their printers and what fixing them will cost. Existing customers may be content telling you just to send someone out, but new customers generally want reassurance that (1) you know what you're talking about, (2) they can afford your service, and (3) you'll respond in a timely fashion.

Companies with three or more techs should invest in a service writer. This person could also do other things, but his or her primary job would be dealing with customers and dispatching techs to solve their problems.

After you've found out who the customer is, and you've taken the pertinent information, learn all you can about the malfunctioning printer. Be absolutely certain that you find out the exact brand and model of printer that the customer is calling about!

While you're on the phone, ask the customer enough questions to effectively isolate and diagnose the problem. In 95 percent of the cases, I can give the customer a firm "not-to-exceed" estimate of repair costs. If that estimate tallies with his concept of value (I know it usually will; my prices are based on research, not guesswork), the customer will nearly always ask me to perform the repair.


Because mine is a customer-oriented company, we diagnose with a method that reflects the customer's complaint or description of the problem. It turns out that all customer complaints generating service requests fall into six general categories:

  1. Power Problems

  2. Communications Problems

  3. Jams (Paper Path Problems)

  4. Image Problems

  5. Noises and Smells

  6. Error Messages

Usually, if a problem falls in the first five categories, there is no error message to help explain what's going on. The big exception to this has to do with paper path problems. If a machine jams, it will generate an error message. In other articles we will discuss real paper jams, error messages and phantom or fake jams. Let's take a close look at each category

  1. Power Problems - The customer says, "I turn on the printer and nothing happens. Please, don't take that as gospel. "Nothing happens" means different things to different people. It can mean everything from "absolutely no noise, light, sound movement or smell" to "it made all the noises, but no paper moved through the machine." When taking the customer's call, ask enough questions to satisfy yourself that you are dealing with the likely failure of a Power Supply or Power Module. In other articles we review, "Power Problems," we'll learn what to ask, how to confirm it, and what the common power problems are on various popular printers.

  2. Communications Problems - These problems represent some of the greatest challenges to technicians and the lowest rewards to his company. The customer sees a computer message that says, "Printer not ready, check cable," or something similar. The true problem is that data will not transfer properly from the host system to the target printer. These types of problems are almost always caused by something other than a printer hardware failure. Consequently, the service company is stuck with the unenviable task of merely proving to the customer that the printer is working properly, and the further unattractive proposition of a one-hour service bill to prove it.

  3. Paper Path Problems - Jams account for more than half of all service calls. Other articles take inside the paper path of the three most popular Canon/HP systems, using them to demonstrate the sort of problems encountered in moving paper through a printer. Common problems of each are discussed in detail, as well as techniques for testing and verifying your diagnosis.

  4. Image Problems -Troubleshooting image problems best demonstrates the need to understand how printers are supposed to work. If you don't know how the image is laid on the paper, it is difficult to determine why a faulty image was produced. This article discusses the various types of image problems, and offers guidelines for their recognition. We'll use the common laser printer engines as examples; the principles you'lI learn from them are nearly universal. All laser printers create an image in precisely the same fashion. Usually the same causes are to blame for a particular type of image defect ( i.e. smeared print) produced by any printer.

  5. Noises and Smells -While I can almost always diagnose a problem resulting from a description of a noise or smell, I will never guarantee it up front. Noises are difficult to localize, and sometimes impossible to eliminate. We'll cover the most common noises, with particular attention to the noises customers complain about most often Smells are easy. There are only two things that can cause them without a more immediate problem.

  6. Error Messages - This article is offered as a guidebook. We have listed all the Hewlett-Packard error messages, and a broad selection of others. We can't, in this manual, comprehensively replace all dedicated machine service manuals, but the error codes listed will guide you in the proper direction.

Writing a comprehensive tech manual is complicated by the fact that different OEMS take different approaches to repair and service. HP takes a "black box" approach, providing tests that help you to isolate failures to the lowest appropriate assembly. Panasonic, on the other hand, offers tests that lead you to board-level repair. For the purposes of this book, we will follow the HP approach; we've done our best to translate all the component-level approaches accordingly.


Every laser printer is an accumulation of various assemblies and subassemblies th work together in a variety of ways. Groups of assemblies are described as "systems." For instance, in the HP laser printer's Paper Handling System is comprised of the (1) Pickup Assembly, (2) Feed Assembly, (3) Main Drive.

What makes this interesting is that the printer Fuser is also part of the imaging system; indeed, it is the final stage in the electrostatic duplicating/printing process. Various assemblies manage to find themselves in one or more systems. While studying troubleshooting, we will frequently refer to various systems. The systems themselves are described in the next article.


For most problems, you will intuitively know the answer from experience. Most machine problems are the same things over and over. For other problems, you'll need to do some diagnostic work. You will need to be able to think logically through the problem, understanding cause and cure.

In the ideal world, you always have two machines. The first, the object machine, is the one that is malfunctioning, the one with the jam, or image problem or error message. The second is the confirmation machine for comparison.

In most instances, you can diagnose a failed machine from a properly working one every time, irrespective of knowledge or training. While this presupposes unlimited time for experimentation, its premise is the fulcrum that good diagnostics rest upon. That is to say, you should be able to export the problem from machine to machine by changing defective assemblies.

Typically you will not be blindly changing assemblies in a frantic search for some mysterious ailment. However, you should take the time to confirm the success of your diagnosis by installing the suspect assembly in the known good machine. The error should follow the assembly. The rules for following this gross method of troubleshooting are simple. You never change more than one assembly at a time, and you are careful to label and track your assemblies. More than one technician has failed dismally and fallen into a pattern of frustration and despair, because he got his assemblies mixed up between working and damaged machines.

This sounds like a lot of trouble and effort, but it is also the way most people begin to learn. If you're dealing with mass-distributed desktop machines this method is practical. With some HP printers, it's a little tedious.


As you gain experience troubleshooting printers, you may fall away from the methods described here. Most repairs undertaken by experienced technicians, after all, are done intuitively, by experience. While you are learning, however, a predetermined method is helpful. Think of it as a road map in an unfamiliar country After all, you don't want to get lost!

Other Helpful HP LaserJet Printer Support Resources

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