HP-19c almost works

[Jonas Sandstedt]

Good to hear that it works, and thanks for the tip regarding changing charge resistor.

I have not had the time to sit down and remove the tantalum capacitors, I think they can be a cause of the problem. I have now arrived at a theory regarding what happens when the printer is running by observing the calculator’s behavior. I think that the calculator makes a quick restart when the printer is running, probably due to a voltage drop such that more complicated calculations are not completed, and always only one line is printed.
I also have a question, can electrolytic capacitors be used instead of the tantalum capacitors?

I have found the schematics at http://www.teenix.org, “Reprinted schematics for Classics, Woodstock, HP-10, and HP-67. Zipped PDF files” at the bottom of the page (thanks Tony for this source of valuable information).

I will come back when I know more.

Best regards Jonas