hp 75 battery contacts

[hfischer]

Hello all,

I just obtained an hp 75 in working condition. It runs from the power supply, but the battery contacts are broken off, there are just some mm sticking out from the case. Two broken-off contacts came with the machine, and I could possibly solder them to the stubs. But in the battery compartment I find three stubs. Two are where I would expect + and -, and a third one is located besides the rear side (-) contact. In the battery pack there is just plastic opposite to this third contact. Is the contact so long that, with the battery pack inserted, it is pressed onto the (-) contact?

Would be nice to know before I try to restore battery functionality.

Thanks in advance,

Helmut, Bremen, Germany

[Paul Berger (Canada)]

Only the two that match the NiCd battery pack are used the third one I understand was designed for a non-rechargeable battery pack that was never produced.

Paul.

[hfischer]

Hi Paul,

(10-08-2019 05:15 PM)Paul Berger (Canada) Wrote:  Only the two that match the NiCd battery pack are used the third one I understand was designed for a non-rechargeable battery pack that was never produced.

thanks for sharing this information.

I checked the scan of the hp 75 user manual on my hpmuseum DVD, and on p. 272 it says "The nickel-cadmium rechargeable battery pack uses the two parallel contacts in the battery compartment" which supports your statement. Additionally, the photo shows the third contact far to the right of the other two.

I just soldered the contacts to the stubs, inserted a refurbished "classic" battery pack - works :-)

Yours, Helmut