Ken Shirriff
We fixed the vintage IBM printer at the Computer History Museum yesterday. Introduced in 1959, the IBM 1403 line printer provided fast, high-quality output, printing 132 character lines. Unfortunately, one column stopped printing, so we disassembled the printer to fix a bad hammer. Keep reading...
Oct 2 at 9:55pmWeb
Show threadKen ShirriffOct 2
The line printer uses a chain with raised characters that spins at high speed. It has 132 hammers, one for each column. When the right character on the chain is in front of a hammer, the hammer fires, printing that character. But if a hammer fails, that column doesn't print, as you can see. 2/N
Show threadKen ShirriffOct 2
We took the hammer unit out of the printer. Fortunately, IBM designed the printer for (relatively) easy maintenance. Inside the printer are two rails that can be attached to the back. The hammer unit slides out and tilts for access. You can see some hammers and coils; more are underneath.
Show threadKen ShirriffOct 2
The hammers looked okay, but @tubetime found that hammer #83 was sticky. He cleaned it and then the printer worked, just in time for the demo. (Stop by the museum on Wednesdays or Saturdays to see the system in operation.) Photo shows a hammer from an earlier repair.
Show threadKen ShirriffOct 2
If you want to know more about the IBM 1403 printer, I wrote about how we played music on it: https://www.righto.com/2019/09/risky-line-printer-music-on-vintage-ibm.html
I also made an animation to explain the extraordinarily complicated timing between the hammers and the chain to print characters: https://static.righto.com/ibm1401/printchain.html
Risky line printer music on a vintage IBM mainframe

At the Computer History Museum , we recently obtained card decks for a 50-year-old computer music program. Back then, most computers didn't...

Show threadMonospace MentorOct 2

@kenshirriff So first there was the printer making music, then there was music on the printer.

https://youtu.be/t7HINgOHwzc?si=0Am3cGMHdLEH2Z9t

Part 2/ IBM 1403 Printer

YouTube
Show threadmathewOct 3

@monospace @kenshirriff I strongly recommend the two albums of printer music by [The User]

https://staalplaatlabel.bandcamp.com/album/symphony-2-for-dot-matrix-printers

(Bandcamp Friday!)

Symphony #2 For Dot Matrix Printers, by The User

12 track album

staalplaat label
Show threadColin BurgessOct 3
@kenshirriff @tubetime so that’s what you guys were fixing!
Show threadRylie Stargazer 🏳️‍⚧️Oct 3
@kenshirriff @tubetime frankly, seems almost more reliable than my modern Epson Eco tank. 😅 (My y2k? era massive IBM info print, aka Lexmark T644, mono laser is at least very reliable, if extremely well used and thus somewhat prone to having toner appear places it shouldn't in the printer. That's probably a closer comparison than a small office inkjet.)
Show threadJ. B. CrawfordOct 2
@kenshirriff I have a powers of two printout hanging on my office door that I believe is from that exact same printer! Someone at CHM gave it to me perhaps a decade ago, I think they'd just recently got it working at the time. Of course we all know that a printer, once fixed, finds a way of breaking again...
Show thread 🇨🇦 CowMan 🇪🇺 🇺🇦 🇲🇽Oct 2
@kenshirriff no video (with sound)?! :( :( :(
Show threadKen ShirriffOct 2
@cowman Here's a video of the printer: https://www.youtube.com/watch?v=Lu4SxJqU9I4
Clair de lune on a line printer

YouTube
Show threadrob pikeOct 2
@kenshirriff There is a legend that night operators would sleep on the printers, only to awaken when the printer opened as the paper ran out, rolling them off the lid to signal it was time to reload.
Show threadrrmuttOct 3
@robpike @kenshirriff I once sent the wrong, much larger, file to one of those, and in the seconds it took me to run to the printer room to stop it, it had printed a stack of fanfold a foot thick.
Show threadrob pikeOct 3
@rrmutt @kenshirriff If the file had formfeed characters, the 1403 could empty a box at seemingly supersonic speeds.
Show threadRodOct 3
@robpike @rrmutt @kenshirriff I once saw Honeywell printer shoot paper several feet up into the air when someone sent a file consisting of all form feed characters. My life as a field engineer was rarely dull because of things like that.
Show threadrob pikeOct 3

@NorwayJose @rrmutt @kenshirriff Yup. I came here just now to tell essentially the same story.

Control characters aren't as much fun any more.

Show threadDavid, a Bostonian in Tokyo.Oct 3

@kenshirriff

IBM donated an IBM 1130 system with a similar, if not the same, line printer to my high school in 1970. I wrote a Conway Life program that printed out Life patterns thereon. (An all-male high school at the time).) A friend and I linked arms and started dancing to the rhythm that the printer made.

The math teacher in charge of the computer opened the door, took one look at us, turned kind of green, and retreated. Rapidly.

We were seriosuly pleased with ourselves.

Show threadmodrobertOct 3
@kenshirriff PC LOAD LETTER