Intermittent black squares printing from Pioneers to 82240B

[BobVA]

(06-07-2017 08:34 PM)Dave Britten Wrote:  ...I tried it with my 17BII a little bit, and was getting similar results, at least as far as the black boxes. I'll have to test again to see if it's dropping initial characters too.

*That* will be interesting!

I think you're right that it could be some subtle timing problem, with your printer and 27S at opposite ends of tolerance, but still it's puzzling it's only the first character.

Maybe the time base for the calculator and the printer are far enough out from each other that getting initial bit sync is taking too long, and if the calculator pauses in sending data (as it might between lines), sync drops and then you get the missed first character while it regains sync?

One way to test that would be to send a long (but less than the 200 character printer buffer length) string of characters that would print several lines, in one burst.
The print stack function would probably do that, or maybe you can do it with the MSG function? If you don't get any dropped first characters with a single buffer full of characters, that's a clue.

Or it could be it's only dropping the first character if it's sent when a <LF> is occurring, which could be some electrical noise problem, as Geoff mentioned. That may be coupled with either a timing problem or a weaker signal from the 27 compared to the 48. The 17BII results will be helpful in ruling that out.

Or you could just use the "A" printer :-) But keep us posted if you press on!