HP-19C Printer

[Jonas Sandstedt]

Hi Tony,

First of all, the HP-19C does not have any Out Of Paper Switch (OOPS). The HP-19C printer is similar to the HP-97 printer, but is not adapted to return to the home position when the characters have been printed, always travelling all the way over the paper width by means of the double-threaded (cross-cut) worm gear. This means that the HP-97 service manual partly is applicable for the HP-19C printer, but the HP-19C printer has less components

I do not I have understood all the problems correctly, but as I understand the situation the motor does not turn on at all in the calculator and you get an Error message, and when externally energized, the worm gear rotates but the printhead does not move.

If this is correct, I think that any, or both, of the motor drive transistors may be broken. You can get tips from Bernhard’s homepage panamatik.de. Go to “Download” and download “HP taschenrechnersammlung 2020” and read from page 96 and forward (it is in English).
If the worm gear rotates but the printhead does not move, there is a small brass bit in the printhead that guides the printhead on the cross-cut worm gear, but it must be pressed towards the worm gear by a tiny spring that can be missing or broken. You find these components when carefully at least partly removing the print-head metal bracket that covers the part of the printhead facing a user. The spring and the underlying brass bit are held in place by the top part of the metal bracket.

I recently bought a HP-19C with the symptoms of the worm gear rotating and the printhead not moving. To my astonishment the spring was no there, it had been removed by a previous owner and probably mislaid. I replaced it with a small spring that I took from a small cylinder lock and now it works perfectly.

I hope the above helps, please come back if you have further queries that I at least can try to answer, or if I have misunderstood something.

Best regards
Jonas