Restoring A Forgotten Dot-Matrix Printer

Dot matrix printers are the dinosaurs that won’t go extinct. They are not unlike a typewriter with the type bars behind the ink ribbon replaced by a row of metal pins controlled by solenoids, each pin being capable of printing a single pixel. At their best they could deliver a surprising level of quality, but their sound once heard is not forgotten, because it was extremely LOUD.

[Wpqrek] bought an old dot-matrix printer, a Commodore MPS 803. Sadly it didn’t live up to the dot-matrix reputation for reliability in that it didn’t work, some of its pins weren’t moving, so he set to on its repair. Behind each of those pins was a solenoid, and after finding a crack in the flexible ribbon to the head he discovered that some of the solenoids were open-circuit. On dismantling the head it became apparent that the wires had detached themselves from the solenoids, so he very carefully reattached new wires and reassembled the unit. Of course, he had no replacement for the flexible ribbon, so he made a replacement with a bundle of long lengths of flexible hook-up wire. This hangs out of the top of the printer as it follows the carriage, but for now it keeps the device working.

Dot-matrix printers are a favourite for our readership. Among others, we’ve seen another Commodore get the Python treatment, as well as an Apple capable of printing in full colour.

14 thoughts on “Restoring A Forgotten Dot-Matrix Printer

  1. Banks still use them, real hard copy that will not fade and low cost per page, I have a dot printhead intended to become a multi micro-valve printhead when time permits, just got to love the old tech.

  2. Though the 803 was utter garbage I do appreciate you posting this as it can be useful for repairing any dot matrix. It was pretty common back in the day to pick up a cheap adapter and use a better centronics style printer (Epson, Oki, etc). CBM printers lacked common features like tractor feed and descenders.

  3. With OSHPark offering flex PCBs now, it might be possible to re-create that broken flex. You might need to laminate an extra layer on to control thickness or flexibility, but it seems possible if you were really interested.

  4. Okidata, Epson and Lexmark still make dot matrix printers at the consumer level (around $500) and there are several companies making high-volume industrial versions. Not as obsolete as one might think.

  5. In a previous job, I used to work for Unisys’ repair centre, fixing broken re-badged Epsons. It tells you how long ago it was, when things were considered worth repairing (1989). They were the cheapest, most cost reduced, boring things i ever worked on. But they were reliable.
    I’ve recently shipped 25 pre-production units of a new product and I would have been very glad of an Epson 80 printer to fill in the multi-part shipping forms.
    Once I’m shipping in higher quantities, I’ll definitely be looking for one. I should be able to fix it if it fails having repaired a couple of hundred of them, 30 years ago. ????

    1. I still have my Star Micronix NX1000, I think it is, in the box in the basement. Bought new in 1989, a few years later I switched to a Mac, and it was easier/cheaper buying a used Apple Imagewriter, than the converter to use a “foreign” and parallel printer with the Mac. So I put it in its box and there it sits. It may not run now, but it was too new to discard back then.

      I found a 24pin printer around 1994, eventually getting rid of it. It was getting harder to find a ribbon, and I had no immediate use for it. But I should have kept that.

      Though, I’ve used laser printers since 2001, and I can’t see myself going back. My used HP 4P died last year, it cost me $15 in 2003 and lasted 15 years, so I bought my first new laser printer in December. Less than the $200 I spent on the NX1000, and way less than the Radio Shack DMP-100 in 1982, about $500, and the Smith Corona daisywheel in 1984, about $400.

  6. Ah those were the times, I got a 120 character extra wide Epson printer that I used on an MSX2 computer. It was dumped by the university my father worked at. He soldered a wire specific for the MSX as it has a different connector. I remember printing hard copies of screen shots of games :) I think I must have some of them in the attic. I used a program that I had to type in from a magazine. It contained machine code, luckily with checksums.
    After that I got an Epson 80 character one, which was faster and had higher resolution fonts. I think I used it with an Amiga 1200, but it was difficult to get the special embedded fonts working with Amiga drivers. It could print nice graphics though.
    At some point I got a second hand laserjet III which lasted a few years. I also owned some inkjets but I rather not think about those dreadful things. Still got the HP 5150 inkjet in the attic somewhere. I use a brother printer for normal prints and pcb creation, which works ok.

  7. The siren song of a dot matrix printing column patterns on the page will stop Hackers Of A Certain Age dead in their tracks. I took one with me to Notacon 8, I believe it was, and ran The Print Shop in dosbox to generate banners, which I hung outside all the conference session rooms.

    While making the banners, people would cruise by in the hallway, stop, and walk backwards to peek into the room. I wish I’d thought to film the phenomenon, it was uncanny.

    The ability to print loooooooong pieces of paper without having to tape individual pages together is something we lost in the inkjet era, and somehow the large-format Designjet beasts just don’t have the same panache!

  8. I remember blowing my 11th-grade computer science teachers mind when I printed a letter for him WITH HIS SIGNATURE AT THE BOTTOM. (It is a ‘Well, DUH!” now, but that was in 1984 on an Apple //e running Applewriter and I had to hand-code the bitmap for his signature, then insert the proper printer commands directly into the document. NOT a trivial exercise.)

  9. Restring process is so easy for laser printer but for dot matrix printer it’s really little bit tough. For dot matrix printer the firmware concept comes over. I was using a Epson printer for long day but for restoration process I must also do the Epson Printer Firmware Reset for all the restoration. So it’s quite hard for me.

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