Back in the 60s, it was I think Digital who first used machinery for semi-automated wire-wrapping of their backplanes. And IBM did too, around the same time. I came across the phrase "Gardner-Denver CNC wire-wrapping machine" in this discussion about a recent repair to an IBM 1403 printer and wondered if I could find footage... and I could!

Here's a few seconds of a Gardner-Denver wire-wrap machine, at 16m48 in the film "Systems that look ahead" by General Electric.

Wow, haven't seen one of those in ages... my Dad used to bring old SMS cards back home when I was a kid... I would pull parts off them and play around with them.... the 1403 printer was used on other IBM machines as well, including the System/3 models 10 and 15D mostly.

The upper end model of the 1403 (model N1, or Nancy-one as we called it) was rated at 1100 lines per minute, or a bit over 18 lines per second. It also featured an acoustic hood that was motor-driven (and would automatically open when it ran out of paper) and the power stacker in the rear for paper. One of the main differences was the use of a "print train" vs the "print chain". This required an improved drive motor setup and a power oiler with it's own reservoir to feed the print train.

All 1403 printers featured a hydraulic drive unit to move the paper. This was a pretty large assembly with two pumps inside driven by a huge 3-phase motor. IIRC, a high-speed skip operation would move paper at 70-IPS (inches per second). The sound-level from the 1403-N1 was extreme... hence the acoustic cover to help keep the deafening noise levels down.

I probably had over 50 of these in my territory back in the late 70's to early 80's. Truly a workhorse printer for decades. It weighed as much as a Volkswagon, had four wheels and a pair of Bus/Tag cables (connecting it to it's controller) that were over 2-inches in diameter... plus the 3-phase power cable. In many ways, I kinda miss the old days of computing

_________________
Regards, KM
https://github.com/floobydust

Had to look that up. Here's a comment from wikipedia talk:

Yes... quite true. The print trains were generally customized for each customer, i.e., some special characters. It could be removed quite easily in a few seconds however... and you used a "feeler gauge" to set the overall clearance of the train to about 0.002" via a small machined opening which had a machined cover bolted in place for normal operation.

Simply put, the print chain used a special ribbon material in a loop to which all of the print slugs (each with 3 characters on them) were attached via two screws and a backing plate. The print train used loose slugs which had 3 characters each and a toothed lower section for drive. One end had the drive spindle and the opposite end had an inductive sensor for synchronization. Needless to say, the train was a heavily machined assembly... and really picky about clearances... hence the 0.002 clearance for ALL print slugs. Get that wrong and the big bang happens within about 5 seconds!

In the latter years, it was pretty rare to have to disassemble the train... we would just have a rebuilt unit shipped as a replacement with the correct print configuration, which was done via a MES number, which was usually hand-written on the train assembly itself.

I did have a few that cratered in the field... usually due to the customer not running the cleaning routine with the sticky pink cleaning paper.... or the CE (Customer Engineer) not properly maintaining the printer. When they cratered (big bang sound), rebuilding in the field would be too time consuming, plus the risk of internal damage to the train housing, gear drive, etc., hence a rebuilt replacement was always the better option.

_________________
Regards, KM
https://github.com/floobydust

I've never seen one of those wire-wrap machines, but have read of them. Interesting.

Gardner-Denver is a very diversified manufacturer that is also well-known for their air compressors. Virtually every Diesel locomotive built in the USA in years past has had a Gardner-Denver two-stage air compressor. The air compressor in my locomotive is a Champion Pneumatic unit, Champion Pneumatic being a division of Gardner-Denver.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

As I understood how the band printers worked, there was a printing hammer for each character position, and the as the band flew by, the appropriate hammer would fire making the type on the page. It was very likely to have several characters printing at the same time. Probably the slowest thing you could print was a line all of the same character.

The one we had in college, boy could that eat paper. The computer/printers used a thing called "Carriage control" which relied on the first character of the line to perform paper handling.

Most notably, if you put a 1 in the first column, it would advance the page. I mistakenly printed a BASIC program with lots of lines starting with 1 (100, 1000, etc.) and forgot to tell it to print without carriage control. I ended up with a 1/3rd of a box of paper in the box, with 1 line per page.

Ken Shirriff's writeup and animation explain how in the 1403 the hammers fire sequentially, in a very satisfying way. (It's linked from the article mentioned in the head post.)
http://righto.com/ibm1401/printchain.html

I had many designs Wire-Wrapped in Massachusetts (MA) in the 80s and early 90s.

I also had a Gardner-Denver WW gun with 30, 24, and 22 AWG bits. Sadly, I cannot seem to find it.

One of the systems that I support today, on and off, was constructed using WW cards and WW backplane. They were originally produced in the early 80s. After being driven over rough roads for 30+ years, many of the systems are still operational. WW technology, when properly installed, is very rugged.

I still haven't put the PDP-11 backplane the BigEd helped me get back the US to use. I suspect that it will work right out of the box.

_________________
Michael A.

Band printers came later... like the IBM 3262/5211 which was a common printer for their System/34, 36 and 38 mid-range systems. These were much smaller, quieter, had speeds up to 650 lines per minute and literally had a metal band that the end-user could remove for cleaning, replacement or swapping for a different character set. The operational principle was the same as the 1403 Chain or Train printing. IIRC, there were either 3 or 4 full sets of characters in the band itself.

Alignment for the band printers was much easier, as there were small rectangular slots in the bottom of the band that were sensed optically and the band was driven by a very large stepper motor. Once the sensors were aligned, they never went out of sync and the printing was always accurate. The metal bands were extremely reliable and maintenance was a simple cleaning which the customer could do themselves. The print ribbon was also a much simpler affair (from the 1403) as it was like a large typewriter ribbon.

So yes, a hammer was located at each print position (132 positions horizontally) and would fire as the characters flew by. There was a very thin mylar band between the hammers and the coil driver armatures (on the 1403)... this was to prevent the slight sticking of the hammer to the metal armature after being fired (which had a residual magnetic field on it). Eventually one of the bands would split/break and the printing became horizontally smeared on the page. It was a simple replacement... no adjustments required. The later band printers alleviated this with a different hammer coil driver design.

As for wire-wrapping, I don't remember what was used at the manufacturing plants... but the gate backplanes were loaded with yellow wires and some black ones too. Every now and then there would be an EC (engineering change) or MES (basically a model number change) that would require field changes to the backplane... usually in the form of removing some wires, adding some wires and in some cases, using a special power tool to cut around one of the WW pins to delete the PCB land pattern to the pin. I do recall seeing a couple guys drill right through the backplane... leaving a small whole where the pin was previously. A very ugly situation as you have no other option than to order a new gate board... not fun.

Still, that was computing back in the 50's through the 80's (and even beyond). All of the machines had multiple gate boards in a swing out door... lots of flat cables with custom connectors to plug into the gates and lots of logic boards that plugged into the gates, which made up the CPU, Storage (control and main), I/O devices, etc. These machines would run for decades 24/7/365 with proper maintenance. Forced air cooling and air filters were standard on the swing out doors as well... including thermal sensors to ensure they didn't overheat, in case the CE wouldn't get around to changing out the filters during PM (Preventive Maintenance).

_________________
Regards, KM
https://github.com/floobydust