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HP Forum Archive 13

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Spice troubles
Message #1 Posted by dbrunell on 27 Aug 2003, 10:48 p.m.

I have a 33E which I acquired recently. It looks brand new, but that is about the only thing positive you can say about it. I got past the trauma of opening the case. Alas, it is a solderless beast.

Here is the trouble I am having. On DC power (2.4 V to the battery terminals), I get no display whatsoever. On AC, I get a flickering display of either all zeros or just a lone decimal point on the left side. Keys seem to have no influence. I tried pressing the flex sandwich this way and that with no noted effect. There is no corrosion on the ICs or flex circuit. It really does look brand new inside and out.

Any ideas? Does anyone have a schematic? I'm thinking it is perhaps a simple problem with the power supply.

One other thing...is the silver 8-pin IC only supposed to have 7 leads?

Thanks and best regards,

David

      
Re: Spice troubles
Message #2 Posted by Jon on 28 Aug 2003, 10:14 a.m.,
in response to message #1 by dbrunell

It is probably a problem of bad connection. Check the flex connector. If that is ok, you probably need spare parts for the circuit or ICs

Cheers

Jon

      
Re: Spice troubles
Message #3 Posted by David Smith on 28 Aug 2003, 2:14 p.m.,
in response to message #1 by dbrunell

Most liekly cause is a crack (often invisible) in on of the conductors in the flex cable from the battery board. Check them with an ohmmeter. Repair involves soldering a wire to replace the offending flex circuit. Often time just jiggling around the flex circuit to fix it will break another conductor. You may have to replace all three conductors.

            
Re: Spice troubles
Message #4 Posted by dbrunell on 29 Aug 2003, 1:20 a.m.,
in response to message #3 by David Smith

>Most liekly cause is a crack (often invisible) in on of >the conductors in the flex cable from the battery board.

Bingo! You da man! Now I have a fully-working, mint 33E to add to the collection.

It must have failed on the original owner shortly after purchase, because the calculator looks like it sat unmolested in its box in a closet for 25 years.

Thank you and best regards,

David

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