It took some work to get the TWIN printers working again. They were dirty, but also several components had disintegrated, and nylon gears had cracked and had to be repaired. I documented my work in the TWIN printer page. As a bonus the page shows a short video of the machine in action.
As with all the Signetics TWIN components the printers are heavy, bulky, noisy and just plain fun to work with. 🙂