Greeting Fritters.I recently (like day before yesterday) acquired an Apple SilenType printer - complete with interface card and a roll of unopened New Stock Apple Branded paper.Well, I seem to have a bad pixel and the stepper motor isn't advancing the paper. I have a part for the stepper motor coming. Hopefully that will solve the latter issue.
Any ideas on how to repair those two issues?
It's a thermal printer. I've never taken one apart so I am not sure how it works internally, but you might be able to see if there is something visibly wrong with that row in the heating element in the print head. Also check for an electrical connection issue. Unfortunately I think it may be a difficult problem to diagnose. I'd start with a careful cleaning and inspection though.
The Silentype is pretty easy to disassemble, just be real careful with the string that pulls the printhead side-to-side. I wouldn't want to have to figure out how to restring it and get the tension right.
I had a similar "dead pixel" problem with mine and managed to clear it up by gently dragging a piece of card stock (which is much thicker than thermal paper) across the paper side of the printhead. I then ran the SilenType demo program which results in a fairly long print-out.
As I recall, there is a flex cable that connects the printhead to the PC board. Make sure it is securely connected and perpendicular to the connectors.
If neither of those things fixes it, you may have a bad heating element in the printhead or a bad ULN2003 driver chip (on the board inside the silentype.)
https://www.applefritter.com/files/2026/04/09/Apple%20Deserializer%20Driver%20Printer%20-%20Schematics%20050-0023-01_0.pdf
I added a diagram, it should help