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How can I dismantle my HP 11C calculator to clean the keyboard contacts. The circuit board will not come out of the front of the case. Thank you.

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Posted on Jan 02, 2017

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SOURCE: My decimal point is now a comma, how do I change

Look for a key or a Left Shift, Right Shift accessed key that has ./,. Might be with the 0 key. (Sorry I have an HP20s .)
Hope it helps.

Posted on Sep 24, 2009

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SOURCE: HP 50G case repair

You should check the HP website to see if the calculator case is considered a replacement part. If it is, you may be able to order one from them.
Hope it helps.

Posted on Sep 27, 2009

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SOURCE: MY HP 11C Calaculaltor has

Try this first. Take out the batteries. Now take a paper clip and bend it into a "U" shape. In the well where the batteries go touch one end of the paper clip to one battery terminal while touching the other end of the paper clip to the other battery terminal. Hold it like this for 30 seconds or so. This effectively dumps any residual charge from the calculator. Now, reinstall the batteries and try turning it on. Assuming this doesn't work I'm afraid you're in the market for a new calculator. HP no longer repairs these so your best bet will be to replace it with the HP35s. The 11c can be found on ebay but they are extremely expensive. Good luck

Posted on Aug 10, 2010

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The HP 32SII calculator has a very common problem with the keyboard connections. There might be nothing else wrong with the calculator except the contacts.

Try pinching the calculator just below the middle of the screen above the [LN] and [Y^x] keys while pushing the [C] button to power it on.

If this worked, at least you know where the problem is. Fixing that problem temporarily, some users wrap a rubber band around the calculator at that point and put something under it to keep pressure on that spot.

The longer-term fix is harder and involves taking the calculator apart to replace a foam pad to keep pressure on the plastic keyboard contact strip against the printed circuit board contacts.

Somebody (not me) put together an Instructables page for the HP 17B calculator, which is built exactly the same as the 32SII.
HP 17b series calculator repair

Nov 30, 2015 | HP 32Sii Scientific Calculator

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Hp 11 c change decimal point

To switch the radix mark, turn the calculator off, press and hold the decimal point key, press the ON key, then release both keys.

Dec 05, 2013 | HP 11c Business/scientific Calculator...

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Why does HP 11C have a c in display

The calculator is set to use compound interest for the odd period. To use simple interest, press STO then EEX.

Apr 22, 2013 | HP 11c Business/scientific Calculator...

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Flashing asterick in left lower screen

That's the low battery indicator. Put in a fresh set of batteries and it will go away.

Mar 29, 2013 | HP 11c Business/scientific Calculator...

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Yamaha psr 550

When PSR550 keys stop working, or are intermittent, in any arrangement, this can be fixed (with work). There is probably TINY dust or debris which prevents a clean key contact from taking place; you must unscrew and open the PSR550 up like a ****, then unfasten the bottoms of the keyboard circuit boards. You can figure out how to move them without totally disconnecting them. You will observe how a tiny rubber-mounted contact presses against an interleaved circuit-board connection pattern to make contact when a keyboard key is pressed. Any dirt or crud on the contact area of the circuit board must be removed, because it will prevent the conductive contact from bridging the circuit cleanly and fully. I used 91% alcohol and QTips to clean all contact surfaces. It took me a couple of disassemble/assemble cycles to get all the keys clean and working, and the PSR550 back together. But first download the service manual: it will show you how to open it and access various components. You will see that the keyboard switches are much like calculator buttons on a TI-83 calculator. They are pretty well enclosed, but you will see how much dust can settle in just through various humidity conditions, especially if you take it to gigs. Good Luck.


Nov 24, 2011 | Yamaha Music

2 Answers

Min eis an HP 11C. flashing 0.00

If the asterisk is flashing, the batteries you put in are not good either.

Sep 12, 2009 | HP 12c Calculator

1 Answer

Dropped my HP 12C into the sink (full of clean water)

Yes, take it apart, and wash the circuit board.
Hard part is taking it apart without breaking the little tabs that snap the case together. It may have a couple hidden screws somewhere like in the batt compartment or under a label or under the rubber feet. Then carefully pry the case joint apart to get the snaps to let loose. Then the circuit board easily comes out - be careful if all the keys are loose not to disturb them. Also be careful of the display that may be loosely mounted. Once you get the board out, you can wash it with soap and water - whatever, just rinse it when clean with something like alcohol so no residues are left. Also be careful to not rub off any off the black key contact spots where the keys touch it. Put it back together loosely and see if it works.
Hope Ya Fixit !!
Fame !

Jun 17, 2009 | HP 12c Calculator

1 Answer

Screen is flashing 0.00

I had the same problem with my HP 11C. The following solution worked for me.
1. Remove the battery cover.
2. With the batteries in place (i.e. DO NO REMOVE THEM), use a small piece of wire (I used a standard staple bent at one end), short the terminals FOR A BRIEF MOMENT between both ends of the set of batteries (the HP-11C has three). This means somehow inserting the staple such that the contacts in the batteries receptacle are shorted.
3. The flashing will stop. Then push the ON button until the calculator turns on. If it does not work the first time, remove the batteries and resinsert them.
4. You may have to repeat this procedure. I had to do it twice before my calculator worked again.

Apr 28, 2009 | HP 12c Calculator

3 Answers

Number 6 on Key Pad, not working

I had the identical problem. One of the fixya folks helped me disassemble the calculator, which I did (there are about 6 plastic rivets which must be reamed away before the circuit board can be lifted out). Be careful not to lose the grounding springs which go back through the two hollow plastic posts. Pull the white sticky covering back carefully, noting which contact represents the "6". Clean the contact area as described but also make sure the contact is in the dead center of the "cut outs" in the sticky film area. When reassembling, I put a small piece of ace bandage between the board and the back of the calculator (towards the bottom, do not block the metal plate where it contacts the "spongy metal" grounding box). This is needed for support since the rivets have been removed.Carefully reassemble everything including the springs. Mine worked perfectly afterward!
I do have a theory that the magnets used in the "anniversary" case have an adverse effect on the calculator. Just a hunch, since one sits over the "6" key. I don't use that case anymore. Sorry they don't make 'em like they used to!

Mar 06, 2008 | HP 12c Calculator

2 Answers

Non functional keys

HP 48SX and HP 48GX calculators have a membrane which connects between the internal circuit boards. This is a common failure point. The "ON" button is often the first button to go out. The calculator can be opened up can cleaned, but it is a little involved. Forutnately someone has posted pictures and information on what to do.

There is a text file with information. The file is big because of the pictures. Summary: Open the case, bend metal clips holding the circuit boards together. Clean up any dust and the contacts. Reassemble.

Sep 21, 2007 | HP 48gx Calculator

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