Troubleshoot common dot matrix printer problems with these techniques

These days, you see fewer and fewer dot matrix printers in corporate environments. However, there are situations where dot matrix printers are still essential, such as when printing on carbon copy forms. Because dot matrix printers are so scarce these days, you’ve probably never touched one. But someday, someone may ask you to fix one. Fortunately, these prehistoric beasts aren’t that complicated to figure out; although, it helps if you have an understanding of the most common dot matrix printer problems and how to solve them. It’s also good to have a few tricks up your sleeve for finding replacement parts and/or printers.

Mystery paper jams
In my experience, the mystery paper jam, a jam with no obvious cause, is by far the most common dot matrix problem. These jams are often caused by a small piece of paper lodged beneath the rollers or beneath the tractor feed. While you can easily remove the rollers on most printers, it’s often easier to go fishing with an unbent paper clip or similar extraction tool.

You will often see this problem after the printer has “eaten” a piece of paper. A large chunk of paper gets trapped under the rollers and then gets bunched up by the printer’s motion, preventing other sheets from passing through the printer. The problem can also occur if, when printing labels, a label separates from the backing and sticks to the rollers.

Mystery jams can also occur when the tractor feed edges separate from the page while printing. Sometimes this can be a fluke, but other times it may point to a mechanical problem. Try taking the paper out of the printer and hitting the form feed button a few times. Watch the printer’s tractor feeds to make sure they are moving and are in synch with each other. Some printers use belts to move the tractor feeds and, over time, these belts wear, break, or become misaligned.

White lines in printed text or graphics
Probably the second most common problem with dot matrix printers is the appearance of horizontal white lines in the middle of printed text or graphics. This almost always signals a problem with the print head. Usually, a pin in the print head has stopped working. I recommend making sure that the print head data ribbon—not the ink ribbon—is connected tightly to the print head. If that checks out, try cleaning the print head with alcohol. Sometimes residue can cause a pin to malfunction. If neither of these tricks solves the problem, you will likely have to replace the print head.

Carriage movement but no printing
When a dot matrix printer’s carriage moves and the printer makes noise but nothing is printed, it usually means the ink ribbon is dried up or missing. If you know the ribbon is good, watch it while printing. The print head should strike the ribbon as printing occurs. Furthermore, each time the print head returns, the printer should advance the ink ribbon. If this isn’t happening, the ink ribbon may be installed incorrectly.

Printing gibberish
If the printer is printing gibberish, try printing some simple text. If you’re able to print plain text but there’s a blank line between each line of text, check the printer’s dip switch, which controls the carriage return and line feed (CR/LF). By toggling this switch, you should be able to correct the problem.

If everything still comes out as gibberish, there are several possible causes—the most likely being an incorrect print driver. For example, if someone tries to print to the printer using a print driver that was intended for a laser printer, the job will print as gibberish. All future jobs will most likely print as gibberish until you have turned the printer off and back on.

A loose, faulty, or overly lengthy printer cable can also cause data to print gibberish. Try switching to a known good printer cable and see if the problem goes away.

If these techniques fail to fix the problem, try generating a print test directly from the printer (not from the computer). If the printer’s internal self-test also prints gibberish, there’s a good chance that the printer’s system board is bad.

Flashing lights
Another problem that you may encounter is that the lights on the printer are flashing. You’ll have to check the printer’s instruction manual for this one. Different flashing patterns mean different things, and the meanings vary among different makes and models of printers. Flashing lights could indicate anything from low ink to a paper jam, to a cooked system board.

No activity at all
If you print to the printer and nothing happens at all, make sure the printer is receiving power and is connected to the PC. If your users are on a network, you should also make sure the PC hasn’t been redirected to a network printer. If nothing seems to work try running a self-test on the printer. If the self-test doesn’t yield any activity, it could be that the motor has burned out or that the system board is fried.

Grinding noise
I’ve seen dot matrix printers make loud grinding noises during printing. More often than not the grinding noise was caused by foreign matter jammed in the printer. Once this foreign matter was removed, the printer returned to normal. However, I have also seen gears strip out on printers because they had worked their way out of alignment. You might try turning off the printer and moving the carriage by hand to make sure everything moves smoothly and that there is no resistance. You should also inspect the belts for excessive wear that would indicate that they have stretched or are about to break.

Finding dot matrix printer parts
If your local computer store doesn’t even acknowledge that dot matrix printers still exist, what do you do when you need a new ink ribbon or spare part for your printer? While searching the Internet may be the obvious solution, I want to share some particularly effective strategies I’ve come across for handling dot matrix availability problems.

Recycle old equipment
This first strategy was used by a tech friend of mine who works for a large organization. The company purchased a sizeable number of Epson LQ-1050 printers in the early 1990s. As laser printers became more affordable, my friend began gradually replacing the dot matrix printers with networked laser printers. He realized, however, that there were a few employees that would always need a dot matrix printer.

To ensure that he would always have replacement parts, he made a habit of taking every dot matrix printer that was phased out and disassembling it. He then separated the various components and stored them in a several bins. One bin was filled with motors, another with print heads, another with gears, and the list goes on. As time went on, the company phased out well over 200 printers. Since there are only three people at the company who still use the dot matrix printers, those people will have spare parts available for a long time to come.

Look for replacements in unconventional places
Another unique strategy I discovered involved a small hospital I supported several years ago. The hospital used dot matrix printers for patient billing. When an invoice was printed, a copy was sent to the patient, another copy was sent to the insurance company, and yet another copy was housed internally. The employee responsible for printing the invoices used an old Epson LQ-1170 printer. One day, the printer died and could not be resurrected.

In a situation like this, I would normally recommend that we buy another printer. Unfortunately, the facility’s billing system was based on proprietary DOS software. The software had the printer codes for the Epson LQ-1170 hard coded into it. So no printer would work except for an Epson LQ-1170.

When the employee asked where to get another printer, I suggested that she check the Internet, particularly eBay or another online auction Web site. That was late on a Friday afternoon. I really didn’t think any more about the problem until the employee called me on Monday morning and asked if I could hook up her printer. Much to my amazement, she had a functional Epson LQ-1170 that appeared to be in really good condition. When I asked where the printer came from, she told me that she always goes to yard sales on the weekends and found the printer at someone’s yard sale for five bucks. Sometimes you just get lucky.

Solutions for the rest of us
If you are in need of a dot matrix printer, printer part, or ink ribbon and you don’t have a storage room full of spare parts at your disposal, and you’re too busy to raid the yard sales, the Internet is probably your best bet.

At the time that I was writing this article, I decided to see if I could locate any dot matrix printers on eBay. I tried searching on Epson LQ-1170, but didn’t have any luck. I then did a search on Epson, and found 198 items for sale. A good number of these were dot matrix printers, and I also found several ink ribbons for sale.

Of course searching eBay to find a mission critical printer or printer part can be a crapshoot. You never know if they will have what you’re looking for. And even if you do find it, it’s often hard to tell if you’re working with someone who is legitimate or how long it will take for it to ship.

If you would prefer a more reliable method of acquiring dot matrix printers, parts, or supplies, there are numerous Web sites, which specialize in printer parts and supplies. You can also check with some of the larger office supply companies. I was really surprised to see that Staples carries an entire line of new dot matrix printers. Don’t expect to find an old LQ-1050 or LQ-1170 in the mix, but if it’s a brand new dot matrix printer that you’re looking for, they’ve got it. I was kind of surprised to see how expensive some of the printers were though. While Staples does offer a dot matrix printer for $199, there were dot matrix printers that cost over $2,500.