HP38C Battery Polarity

[Larry Corrado]

I have an HP38C which I would like to test using a dc power supply connected directly to the battery pack terminals. Does anyone know which terminal is positive? I assume I'll use a double AA voltage of about 2.8 V to test it.

I'm soon to acquire a 38E. I assume it has the same battery pack situation. Is that true?

Thanks!
Larry

[Jim L]

This is from: http://www.hpmuseum.org/batts/battery.htm.

[David Smith]

When installing batteries in a Spice series machine, place a strip of ribbon or paper around the pack to make removing it easier. These machines have a tendency for the battery pack to damage the battery contacts when you remove them. One thing that likes to happen is the bottom (free) end of the battery clip snags between the top contact of the battery and the seam around it. When you try to pry the battery out, the clip snaps off. Not helped by the tendency of the batteries to corrode in these machines.

[Larry Corrado]

Jim: Thanks for the picture and Web reference. I had looked around the HPMuseum for the polarity info, and somehow overlooked it.

David: Thanks for your tips on 30 series batteries.

The machine worked great when I powered it up.

Larry