What kind of batteries does the HP42S use? The owners manual just says it uses 3 button batteries, and the 42S I recently acquired came without batteries, and I want to make sure I get the right kind.

Hi, John;

you can use the same ones designed fot the Voyagers (HP10C to HP16C). They are the same as the National/Panasonic LR44, Eveready/UCAR A76 OR RAY-O-VAC RW82 all alkaline. For a higher current consumption (in case you plain to use the printer output constantly) you can try the Silver Oxide models: Eveready/UCAR 357, RAY-O-VAC RW42 OR 62, Duracell MS76, or others. In fact, these references are taken from the original HP15C Owner's Handbook, dated February 1984... Maybe some of these do not even exist, and even better models are available.

Hope this gives you a clue.

Best regards.

Luiz (Brazil)

I like the Eveready 357. It's a silver oxide battery (lasts longer) and it has received good reviews.

John --

Luiz and John Limpert have given more details, but the simple answer is, three of any type 44, 76, or 357 cells. They are interchangeable, but it's best to use the same chemistry (alkaline or silver oxide). Silver oxide lasts longer but costs more.

HP-42S have a problem of not retaining the contents of memory during battery changes -- maybe a bad batch of capacitors was used, I don't know.

My older-design 42S from 1989 recently survived a battery change with memory contents intact. I also have a newer design 42S from 1992 whose batteries I haven't yet changed.

What experience do others have?

I never had an HP-42S lose memory when I changed the batteries -- this is with 3 different machines, including my current one (1993 model, rev. C).

Thanks for the responses on the battery type.
The last response has me curious. See followup message, seperate posting, on a revision level question.