Put together two designs and sent the boards off to be fabbed; challenge removing typeball from 1053 for more adjustments

REPLACEMENT FOR IBM 1130 CONSOLE LOADER PROJECT

The quick way I implemented the console loader was using two eight relay boards and one four relay board connected to an Arduino. The Console Entry Switches (CES) on the front panel of the typewriter printer are wired to the relays and the other side goes through a resistor to ground. Then there are two buttons, Prog Start and Load IAR, which are wired to three more relays. 

By activating one relay the power is removed from the existing Prog Start switch. The user turns the rotary mode control switch on the 1130 to Load and then uses a terminal program to interact with the Arduino. The text in the file then causes the Arduino to set the CES and push either Load IAR or Prog Start in order to set memory addresses and store contents. 

The issue is one of space and elegance. The relay boards take room under the cover of the 1130, in front of the keyboard, plus we need an additional box elsewhere to hold the Arduino. I designed a board to use optoisolators to replace the relays, that board mounts atop the Arduino and we only need to find a space for that smaller stack inside the console. I sent this off to the fab as well, since I already have the optoisolators and the Arduino. 

MUSEUM DISPLAY CONTROLLER

The Cape Canaveral Space Force Museum has several locations, one of which is outside the security perimeter thus readily accessible to the general public. It has a number of small LCD displays that run various videos discussing activities. These are older units and are behaving very badly. I suspect some kind of corruption to the files as they have repeatedly lost power over the years. 

I decided to whip up a Raspberry Pi based solution that can drive any HDMI monitor as a replacement. It makes use of the Pi Presents open source application to animate such displays. There are a few challenges that aren't properly addressed by the Pi hardware and application. 

Any time power fails, the Linux system running on the Raspberry Pi can leave the file system in a corrupted state since it didn't shut down gracefully. The Pi Presents software can schedule automatic start and shutdown of the displays, but it needs a persistent clock or an internet connection to know the current time. The building does not have internet connectivity. Finally, the staff needs an easy way to start these up for an unscheduled event and to shut them down when leaving at the end of that event. 

I whipped up a circuit that will be built as a 'PI Hat', a board that fits above the Raspberry Pi and plugs into the 40 pin connector. It will provide a real time clock with battery protection so that the system always knows the correct time. It will feature a supercapacitor based system that provides 90 seconds or more of power when the input power drops, plus sends a shutdown signal to Linux, allowing the system to gracefully close all file systems. It has an autostart feature when power comes back on, a start button for manual startup, and a shutdown button that triggers a Linux shutdown. 

This was completed and sent off to the fab for production. It mostly uses surface mount components for compactness. The supercapacitor system that charges the capacitors and then uses them to produce 5V for the machine during power outages is built around a MAX38889 chip. The real time clock is built around a DS3231 chip and a CR2032 battery. The battery needs to be replaced every two years and the capacitors should be replaced every eight years. 

IBM SELECTRIC 1 TYPEBALL BROKEN LEVERS

When IBM first introduced the Selectric typewriter, the typeballs had a plastic lever and cap to remove them from the typewriter, but they soon switched over to a design that had a knurled metal cylinder that the lever was molded onto. The newer construction produced balls that tend to break so that the lever snaps and the element won't detach from the typewriter. The metal cylinder is left on the cap but can't be turned without a lever.

Inside the cap is a strong metal spring that has two arms which snap shut into a groove on the spindle of the typewriter. The metal cylinder has ramped ends that will push the two arms apart so that the ball can be pulled up and off. The lever would cause the cylinder to rotate, that is until it snapped off. This is a very very common failure of these early type elements. IBM eventually went back to all plastic mechanisms which don't break. 

All of the 1053 console printers and most other I/O Selectric devices use the typeballs with metal cylinders, meaning on most of them the ball is stuck on the unit. This doesn't cause a problem in operation but it would be nice to remove the element to clean off built up ink and it is important to make certain adjustments with the ball out of the way. 

The space through the plastic cap to the ends of  the spring arms is very tight, thus ordinary tools like snap ring pliers can't fit in. I will work out a way with my existing tools and perhaps the hardware store to remove the ball for the current restoration, but I want to accomplish two things longer term. First, I want to modify the balls to have a working removal lever. Second, I want to fabricate a tool to easily remove these elements with broken levers.