My Actionwriter came with a continuous ink ribbon cassette. At first I thought there was a patch of ribbon which had no ink on it, because roughly every 2 pages no characters were printed for say 50 keystrokes.

But after trying 2 more ribbons, this time carbon film, and having the same problem, I realised it's probably a fault with the typewriter. I searched for known issues & fixes on the Internet, and at least one other person had asked the same question but there was no answer, so I figured I would post this fix here. At least it seems to be a fix so far!

See photo:



When a key is struck, the whole metal platform holding the cassette lifts up and the piece of plastic A moves forwards, rotating the cog B (under the metal platform) to advance the ribbon. You can see I've put a tiny bit of red marker on the upper cog connected to it (that one slots into the cassette), so I could see if it ever stopped rotating. Sure enough, when typing fast, it occasionally stopped rotating.

It turns out that the piece of plastic A didn't always reliably return to place after moving forward. Moving it forward by hand, it often stuck in the forward position for a moment or two before sliding back. I wondered if it was dragging on the bit of metal below it so used a bit of oil there - no difference. Then I wondered if the unwanted friction was between the bit of plastic and the cog that it was rotating, or thereabouts,  so I put a drop of oil on the cog B and quickly pressed lots of keys to rotate it and spread the oil around.

After that, whenever I move A forward, it reliably returns immediately. So far the Actionwriter has been working fine.

I am not sure what the best type of oil to use was; I had some Wahl Clipper (as in hair trimmer) oil, and used a drop of that. Not sure how long it will last or if it will cause issues?