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HP Forum Archive 16

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batteries for HP32E & 37E
Message #1 Posted by Peter K Mueller on 11 Apr 2006, 9:26 p.m.

Please tell me where to acquire these, or to rig something.

      
Re: batteries for HP32E & 37E
Message #2 Posted by Vieira, Luiz C. (Brazil) on 12 Apr 2006, 1:10 a.m.,
in response to message #1 by Peter K Mueller

Hi, Peter;

I use either two regular NiMH or two regular NiCAD, 1.25Vcc AA size batteries with my spices: HP34C, HP38C (2 units), HP38E, HP37E and HP31E. They are connected in series and the negative goes in the contact closer to the upper edge of the battery connector. Please, have a look at the pictures below: (just click to enlarge)


The small metal plate you see is a single cut from any thin coated metal sheet (coated to prevent oxidation). This one I took from an old 9V battery. You should also take care finding batteries that do not press too much the contact springs, the thin, slightly bent metal tabs. As you can see in the pictures, the ones in my HP34C were pressed too much and they are permanently bent (deformed).

Hope these images give you some guidance. If not, let us know.

Cheers and success!

Luiz (Brazil)

Edited: 12 Apr 2006, 1:16 a.m.

            
Re: batteries for HP32E & 37E
Message #3 Posted by DougT on 13 Apr 2006, 8:17 p.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

Luiz - thanks for the great picture/diagram of the Spice battery flex connector! I have to hard wire one that's corroded out, and this will help out tremendously. Regards, Doug

                  
Repairing Spices - another picture ;-)
Message #4 Posted by Vieira, Luiz C. (Brazil) on 13 Apr 2006, 11:44 p.m.,
in response to message #3 by DougT

Hi, Doug; you're welcome!

Thanks for your kind comments. Please, allow me to show you this one, too:

As you see, I have already done this before... In time: although the flex circuit is the same for both C and E series, the PCB layout for the power circuit is different.

Cheers.

Luiz (Brazil)

Edited: 13 Apr 2006, 11:48 p.m.

            
Re: batteries for HP32E & 37E
Message #5 Posted by Peter K Mueller on 15 Apr 2006, 11:43 p.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

Thanks Luiz. I understand now that the AA batteries must be connected in series. That means the + and - terminals on one end have to be joined with something thin because there is not much room in the case. I have taken an old rechargable nicad 9v battery apart. What plate does one remove? Also I dont understand your picture showing a metal plate the length of the battery case. Shouldnt something metal just be on side opposite from the terminals in the case?

Thanks, again. Peter.

                  
Re: batteries for HP32E & 37E
Message #6 Posted by Vieira, Luiz C. (Brazil) on 16 Apr 2006, 1:21 a.m.,
in response to message #5 by Peter K Mueller

Hi, Peter;

sorry if the pictures did not show the way the contact plate is positioned. The two pictures below might give you the correct information (if needed, click to enlarge):

The plate itself is held by the batteries, so I simply lay it down in the surface opposed to the contacts in the battery compartment, as seen in the picture at the left side. Then I carefully insert one of the batteries, as shown in the picture at the right side, to hold it in place. Now, the other battery is easily inserted.

About the metal plate: I cut it from the external metalic case, as shown in the picture below. BTW, I did not show the other side of the metal plate because it is painted black and gold... Can you figure out which brand? d8^D

Hope this helps. (please, consider that I draw the above picture right now with CorelDRAW!, and it is simply a sketch; to be honest, if I had to make it fancy, I'd not be able to draw it in less than 10 minutes, as I did...)

Cheers.

Luiz (Brazil)

Edited: 16 Apr 2006, 1:41 a.m.

                        
Re: batteries for HP32E & 37E
Message #7 Posted by David Smith on 16 Apr 2006, 11:55 a.m.,
in response to message #6 by Vieira, Luiz C. (Brazil)

When I need Spice batteries I go down to the store an buy a 2xAA cell battery pack for telephones (look for one where the end '+' of the cells has the small protruding button... the totally flat topped packs don't make good contact). I then take off the wiring harness and solder tabs then grind any residue down with a dremel tool.

Finally, I fill in the gap along the top of the cells with PC-7 paste epoxy and half also fill in the top part of the bottom half of the pack. This makes it so you cannot put it in upside down since the battery compartment has that keying rib that sticks up. If your pack is loose in the battery compartment, use some stick on felt or rubber to shim up the end of the pack.

Total cost is about $4.

You can also have your local battery store make you up a custom pack for a few dollars. You will probably have to apply the epoxy yourself. I recommend NiMH cells. Also, many modern batteries will cause the "low battery" light to come on for a few minutes after fully chraging the pack.


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