The Museum of HP Calculators

HP Forum Archive 11

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Message #1 Posted by MarJean on 4 Apr 2003, 7:31 a.m.

I would like to get my hp 11C repaired. It has no response when turned on and I have replaced batteries. The self test does not work. Can anyone help or give me ideas. MarJean

Re: 11C
Message #2 Posted by Randy on 4 Apr 2003, 9:25 a.m.,
in response to message #1 by MarJean

The obvious: Be certain the new batteries are indeed good.

If the problem appeared when you replaced the batteries, that is, it was working before you installed new batteries only to have no response, try the following:

Remove the batteries from the unit. Inside the battery compartment, short the (+) and (-) connections for the batteries together with a bent paper clip. Just a few seconds is all that is required.

Re-install the batteries and try. It should be okay.

Re: 11C (That is, the connections in the CALCULATOR . . .)
Message #3 Posted by Paul Brogger on 4 Apr 2003, 12:34 p.m.,
in response to message #2 by Randy

If I may be so bold as to clarify (to avoid a possible misunderstanding) . . .

I think Randy meant to short the (+) and (-) connections in the calculator. (Touch a bent paper clip or other conductor to them both simultaneously -- this clears any residual voltage in the internal circuitry, to reset the calculator.)

Just in case there's any confusion, those are "the connections for the batteries" in the calculator (not on the batteries).

(Maybe I'm the only one who might have read it the other way!)

Re: 11C - an old issue
Message #4 Posted by Vieira, Luiz C. (Brazil) on 4 Apr 2003, 1:15 p.m.,
in response to message #2 by Randy

Hi, Randy, folks...

In many situations like this one I recomend keeping batteries in place and BRIEFLY shorten their poles. I read soem sutff about it and I think there is some reason on it.

As voltage suppliers, batteries have low internal resistance, so if you touch one pole and you have electrostatic charges, both poles will be equaly charged because batteries are an easy, low-resistance way to connect them. In other hands, if you touch one pole a tenth of a second before connecting to the other and there is electrostatic charges in your finger (or whatever instrument you have used to connect them), chances are that if ESD occurs the calculator will remain in the same "resting" state.

The user's manual for all Voyagers suggests the same: keep batteries in place and briefly shorten their terminals. As they are in place, both batteries and calculator terminals are the same, right Paul? Also, after this discharging procedure, try [ON] and [yx] keys in the same time. Sometimes this procedure "wakens them up".

Just my US$0.01.


Luiz C. Vieira - Brazil

Re: 11C - "Shorting Terminals"
Message #5 Posted by Paul Brogger on 4 Apr 2003, 1:45 p.m.,
in response to message #4 by Vieira, Luiz C. (Brazil)


I generally defer to anyone who uses techincal jargon with more than three syllables.


Sounds good to me!

Re: 11C - Anyway, you're right...
Message #6 Posted by Vieira, Luiz C. (Brazil) on 4 Apr 2003, 5:11 p.m.,
in response to message #5 by Paul Brogger


you're right:

ESD stands for ElectroStatic Discharge.


Luiz C. Vieira - Brazil

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