HP97 The journey begins

[Jonas Sandstedt]

Hello,

I recommend buying new 38mm paper rolls for at least two reasons. First, I think they provide a better print quality, and secondly you can buy roll that are free from bisphenol. Who knows which chemicals that are used for the old original HP rolls? Furthermore, these rolls can be used for several vintage printing scientific calculator, see picture and note the different type faces and styles.

I also want to mention that I have experimented replacing the original HP-19c printhead with a Seiko thermal printer head MTP401B (of the same type as used in the HP82240 printer) – and it worked. The connector is mirrored such that I have to twist the ribbon cable and add cut soldered connector pieces in copper tape (see pictures). The thermal head is not as wide as the HP counterpart, but a small item can be put in the HP-19c printhead holder to keep the new thermal head steady.

Misfortune 1: I accidently bent the new printhead during my experiments such that some of the tiny solder connections connecting the flex wire to the thermal head broke (see deteriorating results in picture), and I do not have a sufficiently small soldering iron. My heart sank and I ceased experimenting. Perhaps a heat gun can do the trick?

Misfortune 2: Seiko discontinued these products in 2021 and the small stocks that have been available for a fair price (about 8-9 Euros a piece) are, as far as I know, depleted.

Best regards Jonas