Hi,
Yes Mark's Hoskins batteries do work flawlessly in the Classics !
To complement Karl's answer, the 19C is not a classic :
It uses a 4xAA battery pack.
The best thing is to use ready-made welded 4xAA or refer to this specific excellent article from Katie Wasserman :
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=335
I differ from Katie in the fact that I prefer not to assemble the pack from scratch but use a 4xAA ready welded pack.
Please note that the rightmost & leftmost elements of the pack must be able to move freely to allow proper positioning in the calc.
Now for the connection to the calc. This connection must be absolutely reliable especially if you intend to charge the battery in the Hp-19C.
So :
- either you go for soldering clips to the pack and then "clip" them to the calculator contacts
- OR you go my way which means soldering the battery contacts to the calculator contacts.
BEWARE : Use a temperature controlled iron AND turn off the iron before soldering to avoid current leaks to the calculator.
The Hp-19C is very fragile and I fail to understand why Hp chose to save a few cents on power regulation & limitation when they designed the Woodstock series.
Oh I forgot : my advice is to avoid NiMH packs for the Hp-19C as I wouldn't rely on the Woodstock charger to charge this type of batteries in the calc.
Best regards from a french Clyde.
Etienne