Electronic troubleshooting is a strange pursuit; it is an activity that falls somewhere between art and science. Success in troubleshooting depends largely on a thorough, logical troubleshooting approach and the right type of test equipment, as well as an element of intuition and luck. This article shows you how to evaluate and determine printer problems, locate technical data, and present a series of printer service guidelines that can ease your work.
The laser printer service & troubleshooting cycle
Define the laser printers symptoms
Identify and isolate printer parts
Repair or replace parts parts
Retest the laser printer
Regardless of how complex your particular circuit or system might be, a reliable troubleshooting procedure can be broken down into four basic steps as shown in Fig. 4-1: (1) define the printer's symptoms, (2) identify and isolate the potential source (or location) of the problem, (3) replace or repair the suspected component or subassembly, and (4) re-test the system thoroughly to be sure that you have solved the problem. If you have not solved the problem, begin again from step 1. The procedure is a universal procedure you can use for any troubleshooting-not just for laser printers.
Define the laser printer’s symptoms
Sooner or later, a laser printer is going to break down. The problem might be as simple as a sticky gear or as complicated as an extensive electronic failure. However, before you open the toolbox, you rust have a firm understanding of the symptoms. You must do more than to simply say, "It's busted." Think about its symptoms carefully Ask yourself what is (or is not) happening. Consider when it is happening.
If this installation is new, ask yourself if the computer is set. up properly, or if the right cables are being used, or if DIP switches are set up correctly. If you have used your laser printer for a while, do you remember the last time you cleaned and lubricated it? Is the print light, dark, or completely missing? Is the paper advancing freely? By recognizing and understanding your symptoms, you will find it easier to trace a problem to the appropriate subsection or components.
Use your senses and write down as many symptoms as you can-whatever you smell, see, or hear. Writing symptoms might sound tedious now, but when you are unto your elbows in repair work, a written record of symptoms and circumstances will keep you focused on the task at hand. Writing symptoms is even more important if you are a novice troubleshooter.
Identify and isolate laser printer parts
Before you try to isolate a problem in the laser printer, first be sure that the printer is, in fact, causing the problem. In many circumstances, printer problems will be obvious, but there are some situations that might appear ambiguous (no print with power on, erratic printing, not enough contrast, etc.).
Always remember that a printer is just a subsection of a larger system including your computer, laser printer, and interconnecting cable. Especially in new installations, a computer failure, software incompatibility, or cable problem might be causing your symptoms.
An easy application of the universal troubleshooting procedure follows. Once you have carefully identified your symptoms, isolate the printer. You can isolate a printer by removing it from its communication cable. You can replace it by testing on another computer system with a working printer (one that you know is working well).
A friend or colleague might let you test your printer on their computer system. Because various computers can be set up to communicate in different fashions, you might have to alter the internal settings of your printer to match those of the working printer.
When printing from an operating system such as Microsoft Windows, you might have to select and configure a new printer driver to support your printer. If your printer exhibits the same symptoms on another computer, there is an excellent chance that the problem is within the printer.
You can then proceed with specific troubleshooting procedures. If, however, those symptoms disappear and your printer works properly, you should suspect a problem in your computer, software configuration, DIP switch settings, printer driver, or interconnecting cable.
Another test is to try a working printer on your computer system. As before, you might need to select another printer driver to operate the working printer properly on your existing system. If another printer works properly, it verifies that the computer, software configuration, and cable are intact.
If a working printer fails to work on your system, check the computer communication interface, software settings and interconnecting cable. Complete this check in addition to testing your questionable printer on another system.
When you are confident that the printer is at fault, you can begin to identify any possible problem areas. Start at the subsection level. You might recall from previous articles that a laser printer consists of several major subsections. Your printer fault will be located in at least one of these subsections or subassemblies. The troubleshooting procedures in previous articles will aid you inn deciding which subsections are at fault.