[GreenKeys] m28 printer adjustments

[Jones, Douglas W]

On Mar 24, 2017, at 9:40 AM, Ken Stritzel wrote:

> i have an m28 printer and when the carriage returns, the second character
> that prints, over prints half of the first character.  i assume there is
> some sort of adjustment?  can anyone steer me to some documentation that
> will help me resolve the over print? - THANKS!  Ken W9AEK

With the m33, there is definitely this problem.  When the carriage returns, it bangs against a stop (a dashpot) and the position of this stop is not necessarily related to the spacing ratchet.  So, instead of landing exactly one space before the next ratchet tooth, it lands 1/2 space before the next tooth, and your first two characters get overprinted.

The m33 manual shows a way to adjust the ratchet.  You put the carriage in the return position and then adjust the ratchet until the ratchet teeth are right relative to the carriage.

I HAVE NEVER DONE THIS.  Instead, I return the carriage with my hand serving the role of the stop in place of the dash pot.  Then, I engage the spacing ratchet and let the carriage sit there in the print position closest to the left margin, held by the ratchet.  Finally, I install the dash pot, adjusting it in its elongated holes so that it's snug against the piston in that position.  The net result is clean spacing as demonstrated here:

-- http://www.cs.uiowa.edu/~jones/pdp8/UI-8/2017/03/07-TTYtorturePrintout.JPG